Posts Tagged ‘fish oil’

Can Fish Oil Make Children Smarter?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues, Supplements and Health

When Do Omega-3 Supplements Make Sense?

Author: Dr. Stephen Chaney

Confused ChildWe know that the omega-3 fatty acids found in fish oil are critically important for brain development. But will they really help our kids learn better? Some studies suggest that they do, while other studies have come up empty. Why is this? More importantly, what does it mean for your children? Will fish oil supplements help or not?

I’ve selected today’s study (Portillo-Reyes et al, Research in Developmental Disabilities, 35: 861-870, 2014) because it sheds some light on those important questions.

Can Fish Oil Make Children Smarter?

This study looked at the effect of supplementation for 3 months with 360 mg of EPA + DHA on cognitive function of malnourished Mexican children, ages 8-12 years old. The children came from poor neighborhoods where foods rich in omega-3 fatty acids were seldom available. Low intake of omega-3 fatty acids was confirmed by a food frequency survey.

Cognition was assessed based on a battery of 16 standardized cognition tests at the beginning of the study and again 3 months later.

The results were fairly clear cut. The children receiving the fish oil supplements showed significant gains in mental processing speed, visual-motor coordination, perceptual integration, attention span and executive function compared to children receiving a placebo. In case you were wondering, the first three most strongly affect a child’s ability to learn and last two affect their tendency to display ADHD symptoms.

What Is the Significance of This Study?

There are a lot of things not to like about the study:

  • It was a small study (59 children total)
  • Blood levels of omega-3 fatty acids were not determined.
  • It was a short term study (12 months would have been better).
  • Measuring the ability to learn is difficult. Experts in the field differ about which cognitive tests are best. I’m not taking a position on the adequacy of the tests they were using because that is not my area of expertise.
  • Because it was done in a poor region of Mexico, one could argue that its applicability to children in this country is uncertain.

 

So why even mention this study? That’s because it illustrates an important principle – one that is often ignored in the design and interpretation of clinical studies.

Simply put, the principle is that not everyone will benefit equally from supplementation. It is the malnourished and the sick who will benefit most. When you focus your clinical studies on those groups you are most likely to observe a benefit of supplementation. When you focus your study on well nourished, healthy individuals it will be much more difficult to observe any benefit. And if you perform a meta-analysis of all studies, without evaluating the studies on the basis of need – nutrition status and health status – benefits will also be much more difficult to demonstrate.

This study is just one example of that principle. In an earlier “Health Tips From the Professor” (Can DHA Help Johnny Read?) I reported on a study looking at the effect of DHA supplementation on reading ability of English schoolchildren. In that study, it was the children who were most deficient in DHA and started with the lowest reading skills who benefitted most from DHA supplementation.

What does all of this mean to you?

  • If you are a parent, you may be asking if a study done with Mexican children eating poor diets has any relevance for your kids. In today’s world of pop tarts and pizza it just might. Most children don’t order sardines on their pizza. As a consequence, many American children don’t get enough omega-3 fatty acids in their diet.
  • Should your children be getting more omega-3s in their diet? A recent study concluded that most American children only get 20-40 mg/day of DHA from their diet. So if your child’s food preferences don’t include salmon, sardines and the like – and if your child is experiencing learning issues or problems with ADHD, you might consider adding fish oil supplements to their diet. There’s no need to megadose. The international standard is around 200 mg/day of DHA for children 7 or older.
  • If you are one of those people who is confused by conflicting headlines about the benefits of supplementation, you may want to look at the studies behind those headlines and ask if supplementation would have been likely to provide any benefit in the subjects studied.

The Bottom Line:

1)     A recent study reported that supplementation with fish oil significantly improved learning skills in children consuming a diet that was deficient in omega-3 fatty acids.

2)     If your children are not consuming foods rich in omega-3 fatty acids such as coldwater fish, you might wish to make sure that they are getting adequate levels of omega-3 fatty acids in their diet. Most experts recommend around 200 mg/day for children over 7.

3)     This study also illustrates the principle that supplementation is most likely to be of demonstrable benefit to those who have the worst diets and the greatest need. That doesn’t mean that supplementation won’t benefit everyone, but it does mean that it may be difficult to prove the value of supplementation in healthy people consuming a good diet.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 

Do Omega-3s Lower Blood Pressure?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues, Supplements and Health

The Good News About Fish Oil

Author: Dr. Stephen Chaney

High Blood PressureHigh blood pressure or hypertension is a major problem in this country. Over 60% of Americans have high blood pressure. Only 47% of those with hypertension are adequately controlled. 20% of them don’t even know that they have high blood pressure.

In this case, ignorance is definitely not bliss. That’s because high blood pressure significantly increases the risk of stroke, heart attacks and congestive heart failure.

The causes of high blood pressure are many. Genetics, obesity, lack of exercise, sodium, alcohol, saturated fats and too few fresh fruits and vegetables all play a role. Age also plays a role. As we age, our blood vessels become less flexible and our blood pressure rises by about 0.6 mm Hg per year.

Medications can help, but many of them have significant side effects and often aren’t fully effective in controlling blood pressure. That’s why natural approaches are so important.

Because there are so many causes of hypertension, natural approaches for lowering your blood pressure are not simple. Natural approaches start with weight loss, restricting sodium intake, increasing physical activity, moderating alcohol intake and something called the DASH diet. In short, there is not just one simple change that you can make that will totally eliminate hypertension. It requires a complete lifestyle change.

That’s why the latest study on the effect of omega-3s on blood pressure is so exciting. If the headlines are true, adding omega-3s to your diet may be one of the most effective things you can do to lower your blood pressure naturally. So let’s examine the study to see if the headlines are accurate.

How Was The Study Designed?

This study (Miller et al, American Journal of Hypertension, doi:10.1093/ajh/hpu024) was a very large, well designed study. It is a meta-analysis of 70 randomized, placebo controlled clinical studies. Key characteristics of these studies were:

  • The mean study duration was 69 days. That means these beneficial effects occur relatively quickly.
  • The mean EPA + DHA dose was 3.8 g/day (range = 0.2 – 15 g/day). A wide range of doses was included.
  • The EPA & DHA came from all sources (seafood, EPA+DHA fortified foods, fish oil, algal oil, and purified ethyl esters. The source did not affect the outcome.
  • Olive oil was the most commonly used placebo, with omega-6 vegetable oils being used as placebos in a few studies. The choice of placebo did not affect the outcome.
  • None of the people in these studies were taking blood pressure lowering medications. That means these studies were specifically designed to see whether omega-3s lowered blood pressure, not whether they had any additional benefit for people already taking medications. This is important because if you only focus on groups who are already taking multiple medications, you tend to obscure the beneficial effects of omega-3s (see my recent Health Tip “Is Fish Oil Really Snake Oil?”)

Do Omega-3s lower Blood Pressure?

Fish OilThe authors of the study reported that:

  • Compared to placebo, EPA+DHA reduced systolic blood pressure (that’s the upper reading) by 1.52 mm Hg and diastolic blood pressure (that’s the lower reading) by 0.99 mm Hg.
  • When they looked at those participants who already had high blood pressure, the numbers were even more impressive – a 4.51 mm Hg decrease in systolic blood pressure and a 3.05 mm Hg decrease in diastolic blood pressure. That’s important because for each 2 mm Hg reduction in blood pressure there is a 6% decrease in stroke mortality, a 4% decrease in heart disease mortality, and a 3% decrease in total mortality.

More to the point, the authors of the study concluded that “A decrease of 4.51 mm Hg in systolic blood pressure among those with high blood pressure could help an individual avoid having to take medication to control blood pressure levels”.

  • When they looked at the study participants who had normal blood pressure the numbers were still significant – a 1.25 mm Hg decrease in systolic blood pressure and a 0.62 decrease in diastolic blood pressure. The authors pointed out that this could prevent, or at least delay, the age-related progression towards hypertension.
  • The effect of omega-3s on systolic blood pressure (4.51 mm Hg decrease) was comparable to the most successful lifestyle interventions – 3-10 mm Hg decrease for 10 pound weight loss, 4-9 mm Hg decrease for increased physical activity, 2-8 mm Hg decrease for sodium restriction, and 2-4 mm Hg for decreased alcohol consumption.
  • A dose of at least 1 gm/day of EPA+DHA was required for a significant decrease in systolic blood pressure, and a dose of over 2 gm/day was required for a significant decrease in both systolic and diastolic blood pressure

While this is a single study, it is consistent with a number of previous studies in this area. Based on the existing body of literature I would recommend omega-3s as part of a holistic approach for keeping your blood pressure under control.

The Bottom Line:

1)     A recent meta-analysis of 70 published clinical studies (AJH, doi: 10.1093/ajh/hpu024) has shown fairly convincingly that omega-3 fatty acids are effective at lowering blood pressure. Moreover, this study is consistent with a number of previous studies. The evidence appears to be strong enough for omega-3s to be considered as part of a holistic approach to keeping your blood pressure under control.

2)     If you already have high blood pressure, you should know that omega-3s caused blood pressure to decrease by 4.51 mm Hg in people like you. The authors of the study concluded that this decrease in blood pressure is large enough that some people may be able to avoid blood pressure medicines entirely. For others addition of omega-3s to their diet will likely allow their physicians to reduce the dose of medications required to keep their blood pressure under control – thus minimizing the side effects of the medications.

3)     If you already have slightly elevated blood pressure that has not yet progressed to clinical hypertension, you should know that omega-3s also give a modest decrease in blood pressure in people like you. The authors of the study concluded that this decrease was enough to prevent or delay the age-related onset of hypertension.

4)     The effect of omega-3s on reducing blood pressure is equivalent to the most successful lifestyle changes (weight loss, increased physical activity, sodium restriction and alcohol moderation). That doesn’t mean that you should pop fish oil pills and forget the other lifestyle changes. The idea is to combine as many of those lifestyle changes as possible so that you may never have to worry about high blood pressure again.

5)     You need at least 1 gm/day of EPA+DHA to reduce systolic blood pressure and more than 2 gm/day to reduce both systolic and diastolic blood pressure.

6)     Contrary to the hype you may have been reading elsewhere, the source of EPA+DHA didn’t matter. The only caveat is that many people really struggle with trying to get 1-2 gm/day of EPA+DHA from fish. It’s a bit too much of a good thing.

7)     Don’t think of hypertension as a “Do it yourself” project. Hypertension is a silent killer. It’s one of those diseases where the first symptom is often sudden death – or, even worse, a life that is no longer worth living. Work with your physician. Let them help you find the right balance between lifestyle changes (including omega-3s) and medications to keep your blood pressure under control.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Is Fish Oil Really Snake Oil?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues, Supplements and Health

Does Fish Oil Reduce Heart Disease Risk?

Author: Dr. Stephen Chaney

Fish OilOne of my readers recently sent me a video titled “Is Fish Oil Just Snake Oil?” and asked me to comment on it. The doctor who made the video claimed that the most recent studies had definitively shown that omega-3 fatty acids, whether from fish or fish oil, do not decrease the risk of heart attack, stroke or cardiovascular death. He went on to say that the case was closed. There was no point in even doing any more studies.

My reader, like many of you, was confused. Wasn’t it just a few years ago we were being told that clinical studies have shown that omega-3 fatty acids significantly reduce the risk of heart disease? Hadn’t major health organizations recommended omega-3 fatty acids as part of a heart health diet? What has changed?

The answer to the first two questions is a resounding YES, and “What has changed?” is THE story.  Let me explain.

Fish Oil And Heart Disease Risk In Healthy People

If we look at intervention studies in healthy people (what we scientists refer to as primary prevention studies) the results have been pretty uniform over the years. In a primary prevention setting, fish oil cannot be shown to significantly reduce the risk of heart disease (Rizos et al, JAMA, 308: 1024-1033, 2012).

That’s not unexpected because it is almost impossible to show that any intervention significantly reduces the risk of heart disease in healthy populations. For example, as I pointed out in recent Health Tips From the Professor (“Do Statins Really Work?” and “Can An Apple A Day Keep Statins Away?”) you can’t even show that statins significantly reduce heart attack risk in healthy populations.

If you can’t prove that statins reduce the risk of heart attacks in a healthy population, it should come as no surprise that you can’t prove that fish oil reduce heart attacks in a healthy population. To answer that question we need to look at whether fish oil reduces the risk of heart attacks in high risk populations.

Fish Oil And Heart Disease Risk In Sick People – The Early Studies

Most of the early  studies looking at the effect of fish oil in patients at high risk of cardiovascular disease (what we scientists refer to as secondary prevention studies) reported very positive results.

For example, the DART1 study (Burr et al, Lancet, 2: 757-761, 1989) and the US Physician’s Health Study (Albert et al, JAMA, 279: 23-28, 1998) reported a 29% decrease in total mortality and a 52% decrease in sudden deaths related to heart disease in patients consuming diets rich in omega-3 containing fish.

Even more striking was the GISSI-Prevenzione study (Marchioli et al, Lancet, 354: 447-455, 1999; Marchioli et al, Eur. Heart J, 21: 949-952, 2000; Marchioli et al, Circulation, 105: 1897-1903, 2002). This was a very robust and well designed study. It looked at the effect of a fish oil supplement providing 1 g/day of omega-3 fatty acids on the risk of a second heart attack in 11,323 patients who had survived a non-fatal heart attack within the last 3 months – a very high risk group.

The results were clear cut. Over the next 3.5 years supplementation with fish oil reduced overall death by 15% and sudden death due to heart disease by 30% compared to a placebo. And, if you looked at the first 4 months, when the risk of a second heart attack is highest, the fish oil supplement reduced the risk of overall death by 41% and sudden death by 53%.

The authors estimated that treating 1,000 heart attack patients with 1 g/day of fish oil would save 5.7 lives per year. That is almost identical to the 5.2 lives saved per 1,000 patients per year by the statin drug pravastatin in the LIPID trial (NEJM, 339: 1349-1357, 1998).

No wonder the American Heart Association said that patients “could consider fish oil supplementation for heart disease risk prevention.”

Fish Oil And Heart Disease Risk In Sick People – The Latest Studies

Heart Health StudyHowever, the most recent studies have been uniformly negative. For example, the ORIGIN trial (Bosch et al, NEJM, 367: 309-318, 2012) treated 12,536 patients who were considered at high risk of heart disease because of diabetes or pre-diabetes with either 1 g/day of fish oil or a placebo. This was also a robust, well designed study, and it found no effect of the fish oil supplement on either heart attacks or deaths due to heart disease.

Similarly, a recent meta-analysis looking at the combined effects of 14 randomized, double-blind, placebo-controlled trials in patients at high risk of heart disease found no significant effect of fish oil supplements on overall deaths, sudden death due to heart disease, heart attacks, congestive heart failure or stroke (Kwak et al, Arch. Int. Med., 172: 686-694, 2012).

No wonder you are confused by all of the conflicting studies. You must be wondering: “Is the American Heart Association wrong?” “Are fish oil supplements useless for reducing heart disease risk?”

What Has Changed Between The Early Studies & The Latest Studies?

When a trained scientist sees the outcome of well designed clinical studies change over time, he or she asks: “What has changed in the studies?” It turns out that a lot has changed.

1)     In the first place the criteria for people considered at risk for heart attack and stoke have changed dramatically. Not only has the definition of high cholesterol” been dramatically lowered, but cardiologists now treat people for heart disease if they have inflammation, elevated triglycerides, elevated blood pressure, diabetes, pre-diabetes or minor arrythmia.

For example, the GISSI-Prevenzione study recruited patients who had a heart attack within the past three months, while the ORIGIN study just looked at people who had diabetes or impaired blood sugar control. While both groups could be considered high risk, the patients in the earlier studies were at much higher risk for an imminent heart attack or stroke – thus making it much easier to detect a beneficial effect of omega-3 supplementation.

2)     Secondly, the standard of care for people considered at risk for heart disease has also changed dramatically. In the earlier studies patients were generally treated with one or two drugs – generally a beta-blockers and/or drug to lower blood pressure. In the more recent studies the patients generally receive at least 3 to 5 different medications – medications to lower cholesterol, lower blood pressure, lower triglycerides, reduce inflammation, reduce arrhythmia, reduce blood clotting, and medications to reduce the side effects of those medications.

Since those medications perform many of the beneficial effects of omega-3 fatty acids, it is perhaps no surprise that it is now very difficult to show any additional benefit of omega-3 fatty acids in patients on multiple medications.

The bottom line is that we are no longer asking the same question. The earlier studies were asking whether fish oil supplements reduce the risk of heart attacks or cardiovascular death in patients at high risk of heart disease. The more recent studies are asking whether fish oil supplements provide any additional benefits in a high risk population that is already on 3-5 medications to reduce their risk of heart disease.

However, the people who are writing the headlines you are reading (and the videos you are watching) are not making that distinction. They are pretending that nothing has changed in the way the studies are designed. They are telling you that the latest studies contradict the earlier studies when, in fact, they are measuring two different things.

Is Fish Oil Really Snake Oil?

Was the doctor who made the video “Is Fish Oil Just Snake Oil?” correct in saying that omega-3 fatty acids are ineffective at reducing the risk of heart disease? The answer is yes and no.

If you take the medical viewpoint that the proper way to treat anyone at the slightest risk of heart disease is with 3-5 medications – with all of their side effects, the answer seems to be pretty clear cut that adding fish oil to your regimen provides little additional benefit.

However, that is not the question that interests me. I’d like to know whether I can reduce my risk of heart attack and cardiovascular death by taking omega-3 fatty acids in place of those drugs – as the original studies have shown.

I’m sure many of my readers feel the same way.

The Bottom Line

  • Studies performed prior to 2000 have generally shown that fish oil supplements reduce the risk of a second heart attack in patients who have previously had a heart attack. One study even suggested that they were as effective as statin drugs at reducing heart attack risk in this population.
  • Recent studies have called into question the beneficial effects of fish oil supplements at reducing the risk of heart disease. However, these studies were performed with lower risk patients and the patients were on 3-5 medications to reduce their risk of heart attack or stroke.
  • The recent studies are no longer evaluating whether fish oil supplements can reduce the risk of heart disease. They are asking whether they have any additional beneficial effects for people taking multiple medications. That’s a totally different question.
  • So ignore the headlines saying that fish oil is snake oil. If you are content taking multiple medications to reduce your risk of heart disease, it is probably correct to say that omega-3 fatty acids provide little additional benefit.
  • However, if you are interested in a more holistic, drug-free approach to reducing your risk of heart disease, I still recommend omega-3 fatty acids as part of a heart healthy diet, as does the American Heart Association.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Do Omega-3 Fatty Acids Decrease Risk Of Depression In Women?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

Do Happy Fish Make Happy Women?

Author: Dr. Stephen Chaney

Woman playing with autumn leaves The days are getting shorter, and those shorter days can lead to depression. You may have seen the recent headlines saying “Omega-3 fatty acids may decrease the risk of depression in women”. If you suffer from seasonal depression, should you be stocking up on fish oil capsules? Let’s look at the study behind the headlines.

The Theory Behind The Study

Depression appears to be increasing in modern society. For example, between 1991 and 2002, the prevalence of major depression has more than doubled in the United States from 3.3% to 7.1%.

There are many causes of depression, but some experts blame the dramatic increase in omega-6 fatty acids in the diet.  For example, per capita consumption of soybean oil, much of it in processed foods, has increased 1000-fold during the past century. That’s a concern because omega-6 fatty acids interfere with the body’s ability to convert vegetable sources of omega-3 fatty acids into the longer chain omega-3 fatty acids thought to be effective in reducing depression.

This has lead to the hypothesis that omega-3 fatty acids in the diet may help prevent depression, and a number of clinical studies have supported that hypothesis.

How Was The Study Designed?

The study (M. A. Beydoun et al, J. Nutr., doi: 10.3945/jn.113.179119, 2013) looked at 1,746 adults age 30-64 living in Baltimore Maryland. The participants were a representative sample of African Americans and whites, men and women. Omega-3 fatty acid intake was based on two 24-hour dietary recalls. Depressive symptoms were based on something called CES-D, which is a 20 item, self-reporting symptom rating scale.

What Did The Study Actually Show?

The results were pretty dramatic for women:

  • Women with the highest intake of omega-3 fatty acids/day were 49% less likely to suffer from depression than women with the lowest intake.
  • No significant effect of omega-3 fatty acid intake on the prevalence of depression was seen for the men in this study. This was the first study to look at men and women separately, so it’s not yet clear whether this is a true sex-specific difference or simply due to the relatively small sample size and reduced incidence of depression in men.

Limitations Of The Study:

There were numerous limitations to this study, but the most important were:

  • It did not ask whether the participants were taking fish oil supplements, and it did not substantiate the dietary recalls by measuring actual levels of omega-3 fatty acids in the blood.
  • It just measured associations, not cause and effect.

The Bottom Line:

This is not a particularly strong study, but it is consistent with a least half a dozen other studies that have obtained similar results. So, based on the total body of published studies my recommendations are:

1)     If you are a woman and you’re suffering from mild depression you might want to talk with your doctor about increasing your omega-3 fatty acid intake before you start taking an anti-depressive medication. Omega-3 fatty acids may reduce heart disease risk, lower inflammation and provide other benefits. The drugs generally have side effects rather than side benefits.

2)    We don’t have any good data yet on what dose of omega-3 fatty acids are needed, but the 500-1,000 mg/day that the NIH recommends for heart health might be a good starting place.

3)     If you’re a guy, this paper suggests that the jury is out about whether omega-3s can help you with depression. More studies will be required. In the meantime, just remember that omega-3s have lots of other health benefits.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Do Omega-3 Fatty Acids Cause Prostate Cancer?

Written by Steve Chaney on . Posted in Food and Health, Issues

Fish, Fish Oils And Prostate Cancer

Author: Dr. Stephen Chaney

Pure Fish OilMy phone has been ringing off the hook. My email in-box is full. It seems that everyone wants to know if the headlines about omega-3 fatty acids and prostate cancer are true.

In case you have just gotten back from a vacation on some deserted island with no newspapers and no internet, let me bring you up to date. The headlines are saying things like “Fish Oils May Increase Your Risk of Prostate Cancer” and “Latest Study Links Fish Oils to Prostate Cancer”.

Once again, it seems like just when you’ve figured out which foods that are good for you, someone tells you they could actually kill you. It’s no wonder so many of you have been asking me to cut through the hype and put this latest study in perspective.

What the study actually says:

As usual, let me start with the study itself (Brasky et al., Journal of the National Cancer Institute, doi: 10.1093/jnci/djt174). On the surface, it appears to be a reasonably well designed study, and the conclusions were dramatic. They reported that subjects with high levels of omega-3 fatty acids in their blood were 43% more likely to develop prostate cancer, 44% more likely to develop low grade prostate cancer, and 71% more likely to develop high grade prostate cancer compared to those with low levels of omega-3 fatty acids in their blood.

The flaws in the study:

Case closed you might be tempted to say. However, once you dig a little deeper, the study does have two important weaknesses.

1)     It used data from another study that was designed for a totally different purpose. They went back and analyzed blood samples from a previous study that was actually designed to measure the association between vitamin E and selenium intake and prostate cancer. That’s a scientific no-no.  Let me explain why.

If they had designed a study to investigate the association between omega-3 fatty acids and prostate cancer, they probably would have selected participants with a wide range of omega-3 fatty acids in their blood at the beginning of the study. The subjects in this study actually had a very narrow range of omega-3 fatty acids in their bloodstream.

They also would probably have done a diet analysis and found out whether the subject’s omega-3 fatty acids were coming from fish or fish oil supplements. They might have even asked whether the omega-3 fatty acids were from farm-raised fish or inexpensive fish oil supplements known to be contaminated with PCBs. This study collected none of these data.

2)     This is a single study, and individual studies often provide misleading results. For example, if you examine their data closely, it looks like heavy drinkers and smokers might have a decreased risk of prostate cancer. I think that’s unlikely, but weird associations like that often pop up in individual studies.

What do you find when you look at other studies?

Expert scientists aren’t swayed by individual studies. We prefer to look at the “big picture” that emerges when you combine the results of many studies. For example, a meta-analysis of 24 studies with 461,402 subjects (Symanski et al, American Journal of Clinical Nutrition, 92: 1223-1233, 2010) found no association between fish consumption and prostate cancer risk.

Individual studies ranged from a 61% decrease in risk to a 77% increase in risk, but the overall effect was zero! Even more importantly, fish consumption decreased prostate cancer deaths by 63%.

The Bottom Line:

1)     Don’t panic. Don’t change what you are doing based on the latest sensational headlines. This study has been way overblown. We have come to expect sensational headlines and hype from journalists and bloggers because that’s how they get people to read what they write.

However, I find the comment from the senior author that “We’ve shown once again that use of nutritional supplements may be harmful” to be very irresponsible, especially since they have no data showing that anyone in their study actually used fish oil supplements.

2)     The benefits of assuring optimal omega-3 fatty acid intake clearly overshadow the risks. Omega-3 fatty acids have been shown to lower triglycerides and blood pressure, reduce inflammation and depression, and may even help prevent dementia.

3)     This study does raise a caution flag, but I would not recommend reducing your omega-3 fatty acid intake on the basis of these data alone – especially since most published studies show no increased risk of prostate cancer. There are much better designed studies underway that should clearly show an increase in prostate cancer risk if it is a real effect. I will monitor those studies closely and keep you abreast of any new developments.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Omega-3 Fatty Acid Deficiency And ADHD: Do The Effects Worsen From Generation to Generation

Written by Steve Chaney on . Posted in Food and Health, Issues

The Seventh Generation Revisited

Author: Dr. Stephen Chaney

Angry boy portraitDo the effects of omega-3 fatty acid deficiency on ADHD get worse from one generation to the next?

When I was a young man I read an article called “The Seventh Generation” in Organic Gardening magazine. That article was based on the old Indian admonition to consider the effects of everything we do on the seventh generation of our descendents.

The article was written before the environmental movement had co-opted the seventh generation concept. It was also written at a time when the food industry and the public had really started buying into the “better living through chemistry” concept. Processed foods, fast foods and artificial ingredients had just started to replace real foods in the American diet.

The author envisioned a world in which, if we continued to eat nutrient depleted foods, each generation would be sicker than the previous generation until by the seventh generation our descendents would live miserable, sickly, shortened lives – and nobody would know why.

That article made a powerful impression on me. I always like to keep my mind open to new ideas, especially ideas that challenge my preconceived thinking.

So I asked myself “Could it be true? Could eating nutrient depleted foods actually make each generation sicker than the previous generation?”

The author did not have the foresight to predict the obesity epidemic, so he did not envision a world in which we might live sicker, shorter lives in as little as one or two generations.

In addition the author was not a scientist, and his whole premise seemed scientifically implausible at the time. In those days we thought of DNA as the sole determinant of our genetic potential and as something that could not be influenced by our environment. Now we know the DNA and the proteins that coat the DNA can be influenced by the foods we eat and other environmental factors – and that those changes can be passed down from generation to generation. This has lead to a whole new scientific discipline called epigenetics.

Could it be true?

All of that leads me to this week’s article (Bondi et al, Biological Psychiatry, doi:10.1016/j.biosych.2013.06.007). Let me start by pointing out that this is an animal study. It was done with rats. I usually base my health tips on human clinical trials, but it is simply not possible to do multi-generation studies in humans.

The authors hypothesized that omega-3 fatty acid deficiency could be associated with psychiatric disorders such as ADHD, autism, schizophrenia and depression. They based this hypothesis on the known role of omega-3 fatty acids in both brain development and maintenance of normal brain function. They also pointed to numerous clinical studies showing that omega-3 fatty acids could either prevent or reduce the severity of these diseases in humans.

They focused on adolescent rats as well as adult rats because these diseases frequently emerge, and are sometimes more severe, during the adolescent years in humans. Finally, they included second generation rats in the study because the change in our food supply that created an excess of omega-6 fatty acids and a deficiency of omega-3 fatty acids started in the 1960s and 1970s. They reasoned that if the effect of omega-3 deficiency is multigenerational it would be more severe in today’s human adolescents. As I said before, you can’t do multigenerational studies in humans, but you can do them in rats.

They separated litters of rat pups from omega-3 sufficient parents into two groups. One group was fed a diet sufficient in omega-3 fatty acids, and the second group was fed an identical diet except that it was deficient in omega-3 fatty acids. When the omega-3 sufficient group reached adulthood, they were mated and their offspring were continued on the same omega-3 sufficient diet. Similarly, when the omega-3 deficient group reached adulthood, they were mated and their offspring were raised on the same omega-3 deficient diet.

They put each group of rats through a series of behavioral tests when they were adolescents and again when they were adults. It is beyond my expertise to analyze the validity of rat behavioral assays, but the authors claim that the tests they employed were good measures of behavioral traits in human that would be classified as hyperactivity, anxiety, attention deficit disorder and reduced behavioral flexibility. [If you have adolescents in your household, some of those behaviors may sound awfully familiar].

The results were thought provoking. They found little evidence that omega-3 fatty acid deficiency triggered these behaviors in the first generation rats. However, they found strong evidence that omega-3 fatty acid deficiency triggered each of those behaviors in the second generation rats – and the effect was much stronger in the adolescent rats than in the adult rats.

The Bottom Line

At the present time, it isn’t possible to predict the significance of this study for you. This is a single study. And, it is an animal study. It could mean nothing, or it could mean everything.

We do know that the incidence of ADHD in US children has increased by 38% from 2003 to 2012 – and nobody really knows why. We also know that some studies have shown that the American diet is often deficient in omega-3 fatty acids. These same studies have suggested that providing adequate amounts of omega-3 fatty acids in the diet may prevent or reduce the symptoms of ADHD.

I’m a hard-nosed scientist. So I’m not going to be one of those bloggers who writes sensational headlines claiming that omega-3 fatty acid deficiency, or some other nutritional factor, is the cause of our skyrocketing rates of ADHD.

But, it is enough to make you wonder “What if? Could it be true?”

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Can Plant-based Diets Be Unhealthy?

Posted September 10, 2019 by Dr. Steve Chaney

Do Plant-Based Diets Reduce Heart Disease Deaths?

Author: Dr. Stephen Chaney

 

plant-based diets vegetablesPlant-based diets have become the “Golden Boys” of the diet world. They are the diets most often recommended by knowledgeable health and nutrition professionals. I’m not talking about all the “Dr. Strangeloves” who pitch weird diets in books and the internet. I am talking legitimate experts who have spent their life studying the impact of nutrition on our health.

Certainly, there is an overwhelming body of evidence supporting the claim that plant-based diets are healthy. Going on a plant-based diet can help you lower blood pressure, inflammation, cholesterol and triglycerides. People who consume a plant-based diet for a lifetime weigh less and have decreased risk of heart disease, diabetes, and cancer.

But, can a plant-based diet be unhealthy? Some people consider a plant-based diet to simply be the absence of meat and other animal foods. Is just replacing animal foods with plant-based foods enough to make a diet healthy?

Maybe not. After all, sugar and white flour are plant-based food ingredients. Fake meats of all kinds abound in our grocery stores. Some are very wholesome, but others are little more than vegetarian junk food. If you replace animal foods with plant-based sweets, desserts, and junk food, is your diet really healthier?

While the answer to that question seems obvious, very few studies have asked that question. Most studies on the benefits of plant-based diets have compared population groups that eat a strictly plant-based diet (Seventh-Day Adventists, vegans, or vegetarians) with the general public. They have not looked at variations in plant food consumption within the general public. Nor have they compared people who consume healthy and unhealthy plant foods.

This study (H Kim et al, Journal of the American Heart Association, 8:e012865, 2019) was designed to fill that void.

 

How Was The Study Done?

plant-based diets studyThis study used data collected from 12,168 middle aged adults in the ARIC (Atherosclerosis Risk in Communities) study between 1987 and 2016.

The participant’s usual intake of foods and beverages was assessed by trained interviewers using a food frequency questionnaire at the time of entry into the study and again 6 years later.

Participants were asked to indicate the frequency with which they consumed 66 foods and beverages of a defined serving size in the previous year. Visual guides were provided to help participants estimate portion sizes.

The participant’s adherence to a plant-based diet was assessed using four different well-established plant-based diet scores. For the sake of simplicity, I will include 3 of them in this review.

  • The PDI (Plant-Based Diet Index) categorizes foods as either plant foods or animal foods. A high PDI score means that the participant’s diet contains more plant foods than animal foods. A low PDI score means the participant’s diet contains more animal foods than plant foods.
  • The hPDI (healthy plant-based diet index) is based on the PDI but emphasizes “healthy” plant foods. A high hPDI score means that the participant’s diet is high in healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) and low in animal foods.
  • The uPDI (unhealthy plant-based diet index) is based on the PDI but emphasizes “unhealthy” plant foods. A high uPDI score means that the participant’s diet is high in unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) and low in animal foods.

For statistical analysis the scores from the various plant-based diet indices were divided into 5 equal groups. In each case, the group with the highest score consumed the most plant foods and least animal foods. The group with the lowest score consumed the least plant foods and the most animal foods.

The health outcomes measured in this study were heart disease events, heart disease deaths, and all-cause deaths. Again, for the sake of simplicity, I will only include 2 of these outcomes (heart disease deaths and all-cause deaths) in this review. The data on deaths were obtained from state death records and the National Death Index. (Yes, your personal information is available on the web even after you die.)

 

Do Plant-Based Diets Reduce Heart Disease Deaths?

plant-based diets reduce heart deathsThe participants in this study were followed for an average of 25 years.

The investigators looked at heart disease deaths over the 25 years and compared people with the highest intake of plant foods to people with the highest intake of red meat and other animal foods. The results were:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

What Else Did The Study Show?

The investigators made a couple of other interesting observations:

  • The association of the overall diet with heart disease and all-cause deaths was stronger than the association of individual food components. This underscores the importance of looking at the effect of the whole diet on health outcomes rather than the “magic” foods you hear about on Dr. Strangelove’s Health Blog.
  • Diets with the highest amount of healthy plant foods were associated with higher intake of carbohydrates, plant protein, fiber, and micronutrients, including potassium, magnesium, iron, vitamin A, vitamin C, folate, and lower intake of saturated fat and cholesterol.
  • Diets with the highest amount of unhealthy plant foods were associated with higher intake of calories and carbohydrates and lower intake of fiber and micronutrients.

The last two observations may help explain some of the health benefits of plant-based diets.

 

Can Plant-Based Diets Be Unhealthy?

plant-based diets unhealthy cookiesNow, let’s return to the question I asked at the beginning of this article: “Can plant-based diets be unhealthy?” Although some previous studies have suggested that unhealthy plant-based diets might increase the risk of heart disease, this study did not show that.

What this study did show was that an unhealthy plant-based diet was no better for you than a diet containing lots of red meat and other animal foods.

If this were the only conclusion from this study, it might be considered a neutral result. However, this result clearly contrasts with the data from this study and many others showing that both plant-based diets in general and healthy plant-based diets reduce the risk of heart disease deaths and all-cause deaths compared to animal-based diets.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

There is one other subtle message from this study. This study did not compare vegans with the general public. Everyone in the study was the general public. Nobody in the study was consuming a 100% plant-based diet.

For example:

  • The group with the highest intake of plant foods consumed 9 servings per day of plant foods and 3.6 servings per day of animal foods.
  • The group with the lowest intake of plant foods consumed 5.4 servings per day of plant foods and 5.6 servings per day of animal foods.

In other words, you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet.

 

The Bottom Line

A recent study analyzed the effect of consuming plant foods on heart disease deaths and all-cause deaths over a 25-year period.

When the investigators looked at heart disease deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

A more subtle message from the study is that you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet. The people in this study were not following some special diet. The only difference was that some of the people in this study ate more plant foods and others more animal foods.

For more details on the study, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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