Are Attention-Deficit/Hyperactivity Disorder Symptoms Affected By Diet?

Written by Dr. Steve Chaney on . Posted in ADHD Diet, ADHD Symptoms

What Can You Do To Reduce ADHD Symptoms In Your Child?

Author: Dr. Stephen Chaney

 

attention deficit hyperactivity disorderAttention-Deficit/Hyperactivity Disorder rates for American children are skyrocketing. One study reported that the percentage of children diagnosed with ADHD has increased by 43% between 2003 and 2011. Another study reported an increase of 67% between 1997 and 2015. Currently, 10-12% of American schoolchildren are diagnosed with ADHD. That amounts to around 6 million children with Attention-Deficit/Hyperactivity Disorder.

The reason for the rapid increase in ADHD symptoms is controversial.

  • Some experts claim the increase simply reflects more accurate diagnostic protocols.
  • Others say the increase is driven by aggressive marketing of ADHD drugs by pharmaceutical companies.
  • Others feel the cause is environmental, with the worsening American diet and increased exposure to toxins in everyday consumer products being named as the most likely culprits.

Attention-Deficit/Hyperactivity Disorder Side Effects

 

62% of children diagnosed with Attention-Deficit/Hyperactivity Disorder are taking ADHD medications. These medicines reduce, but do not eliminate, ADHD symptoms. But the improvements come at a high price. Side effects include:

  • Sleeping problems.
  • Reduced taste perception.
  • Loss of appetite.
  • Anxiety, moodiness, and irritability.
  • Headaches and stomachaches.

Because of the side effects of ADHD medicines, parents often look for more natural solutions. Many of them report that improving their child’s diet reduces their child’s ADHD symptoms as well or better than ADHD medications. Are their opinions accurate, or do the child’s ADHD symptoms improve just because their parents are paying more attention to them?

The latest headlines proclaim that improving a child’s diet does not reduce their ADHD symptoms. Are those headlines correct, or do parents know something that the scientists missed?

To answer those questions, we should start by looking at the study (https://doi.org/10.1093/jn/nxy273) behind the headlines.

 

How Was The Study Done?

 

attention deficit hyperactivity disorder studyThe authors of this study analyzed data from 3680 children who were involved in the Generation R Study in Rotterdam, Netherlands. This study measured the association between Attention-Deficit/Hyperactivity Disorder symptoms and diet quality.

However, this was not a simple association study. It was something called a prospective cohort study. That means rather than measuring the association at a single time like most studies, this study measured ADHD symptoms at age 6 and 10 and diet quality at age 8.

Attention-Deficit/Hyperactivity Disorder symptoms were assessed by using parent-reported questionnaires. Dietary intake was assessed by using a validated food frequency questionnaire filled out by the parents. Diet quality was based on comparing a child’s dietary intake to the Dutch dietary recommendations for children (Which are not significantly different from the US dietary recommendations).

 

Are Attention-Deficit/Hyperactivity Disorder Symptoms Affected By Diet?

 

The results of the study were confusing:

  • ADHD symptoms at age 6 were associated with poorer diet quality at age 8.
  • However, there was no association between diet quality at age 8 and ADHD symptoms at age 10.

The author’s conclusions, which generated the headlines you may have seen, were even more confusing.

Based on the first finding (Attention-Deficit/Hyperactivity Disorder symptoms at age 6 associated with poorer diet quality at age 8), they concluded “…children with more ADHD symptoms may be at a higher risk of an unhealthy diet.” They hypothesized:

  • ADHD symptoms may cause “…impulsive eating of highly palatable foods or no patience to eat vegetables…”
  • “…parents try to soothe difficult behavior of their children by offering meals, snacks, and beverages children prefer instead of healthy choices.”

Based on the second finding (diet quality at age 8 having no relationship with ADHD symptoms at age 10), they concluded “…overall diet quality does not affect ADHD risk.”

In short, they concluded that Attention-Deficit/Hyperactivity Disorder caused poor diets, but poor diets did not cause ADHD.

 

Are The Conclusions Of This Study Accurate?

attention deficit hyperactivity disorder thumbs downThe authors identified several important limitations of their study. For example, they acknowledged:

  • They relied on parent reporting of both ADHD symptoms and dietary intake.
    • Parents may have found it difficult to assess ADHD behavior in their children.
    • Parents may not have known what their children consumed at school or during after-school care.
  • Both dietary intake and ADHD symptoms may change over time.
    • ADHD symptoms are different at age 6 and 10, so two different ADHD assessment questionnaires were used.
    • Parents have less control (and knowledge) of their child’s diet at age 10 than at age 8. The dietary assessment at age 8 might not have been valid for the children two years later.

However, to me the two biggest weakness of the study were:

  • All the children in the study had ADHD symptoms at both ages 6 and 10. These were the same children! That makes the fact that ADHD symptoms correlated with diet quality at age 6, but not at age 10 highly suspect.
  • ADHD symptoms and diet quality were measured at different times. This is a bizarre experimental design. The study would have been much stronger if the authors had measured both diet quality and ADHD symptoms at each age.

In short, this study is fatally flawed. The conclusions of the study are inaccurate. You should ignore the headlines.

 

What Can You Do To Reduce Attention-Deficit/Hyperactivity Disorder Symptoms In Your Child?

 

attention deficit hyperactivity disorder questionThe recent study does illustrate the difficulty in proving diet-ADHD interactions. The truth is ADHD is a complex condition. It is affected by genetics, environment, family interactions, and food. This is best illustrated by a review written by two pediatricians specializing in ADHD that I featured in ADHD Diet vs Medication of “Health Tips From The Professor.”

The authors of the review described multiple nutritional approaches that reduce ADHD symptoms. The catch was each nutritional intervention only worked for some children. Parents needed to be willing to find what works best for their child by trial and error. Let me give some examples.

  • Eliminating Food Additives: The idea that food additives cause ADHD symptoms originated with the Feingold diet which was popularized in the 1970s. The Feingold diet eliminated food additives, foods with salicylates (luncheon meats, sausage, hot dogs), drinks containing artificial colors and flavors, and chemical preservatives (e.g. BHA and BHT). After clinical studies showed that only 6% percentage of children benefitted from this diet, it fell out of favor.

However, the experts who pooh-poohed the diet missed a key point. Yes, 6% is a very small percentage of the general population. However, if you are one of those parents whose child is in the 6%, this approach works wonders. A recent study showed that when children with suspected sensitivity to food additives were challenged with food colors, 65-89% of them displayed ADHD sensitivities.

My recommendation: Food additives are not one of the five essential food groups. There is no reason not to eliminate food additives from your child’s diet, and it might make a world of difference for their ADHD symptoms.

  • Adding Omega-3 Fatty Acids: The authors of the review reported that several studies have shown children with ADHD tend to have low levels of omega-3 fatty acids. They also cited several studies which showed significant improvement in reading skills and reductions in ADHD symptoms when children with ADHD were give omega-3 supplements. It was usually the children with the lowest omega-3 status who showed the biggest improvement in ADHD symptoms.

attention deficit hyperactivity disorder symptomsThe pediatricians who wrote the review routinely use doses of 300-600 mg of omega-3s with their ADHD patients. They find that this intervention reduces ADHD symptoms in many children but does not completely eliminate the need for medications.

My recommendation: Whether adding omega-3s will help your child is anyone’s guess. However, it is a natural approach with no side effects. It is definitely worth trying.

  • Adding Iron and Zinc: Some studies have suggested that iron and zinc deficiencies may be associated with ADHD symptoms.

My recommendation: A good children’s multivitamin should be sufficient to eliminate these deficiencies.

  • Eliminating Sugar: This recommendation is controversial, but the authors of the review said it helps some of the children they treat reduce their ADHD symptoms.

My recommendation: Reducing intake of refined sugars in your child’s diet makes sense for many reasons, especially considering the role of sugar intake in obesity. If it also reduces ADHD symptoms, that is an added benefit.

  • Eating A Healthy Diet: Several studies have shown that children eating “Healthy” diets (fish, chicken, vegetables, fresh fruit, whole grains & low fat dairy products) have fewer ADHD symptoms than children eating “Western” diets (Fast foods, red meat, processed meats, processed snacks, high fat dairy products & soft drinks).

My recommendation: Again, this is an approach that makes sense for many reasons. If you and your family were to follow a “Healthy” diet instead of a “Western” diet, it would likely have numerous health benefits. Plus, you would automatically remove ADHD triggers such as food additives and sugar from your child’s diet.

  • Eliminating Food Sensitivities: If you have tried everything and your child’s ADHD symptoms are as bad as ever, your child may have a sensitivity to a perfectly healthy food. Even natural foods can be a problem for children with food sensitivities, and it appears that there may be a large percentage of hyperactive children with food sensitivities. The authors of the review reported that elimination diets (diets that eliminate all foods which could cause food sensitivity) improve behavior in 76-82% of hyperactive children.

Even though this approach can be very effective they don’t normally recommend it for their patients because it is difficult and time-consuming. The elimination diet is very restrictive and needs to be followed for a few weeks. Then individual foods need to be added back one at a time until the offending food(s) are identified. (They also reported that antigen testing is not a particularly effective way of identifying food sensitivities associated with hyperactivity).

My recommendation: I view this as something to be tried after all other natural approaches have failed. However, if there is a particular food that causes hyperactivity in your child, identifying it and eliminating it from their diet could be something that would benefit them for the rest of their life.

 

The Bottom Line

 

You may have seen recent headlines suggesting that healthy diets do not reduce ADHD symptoms. In fact, the study behind the headlines concluded that ADHD may cause poor diets, but poor diets do not cause ADHD.

My mission in writing “Health Tips From the Professor” is to analyze the studies behind the headlines and tell you whether you can believe the headlines or not.

In this case my analysis is clear-cut.

  • The study is fatally flawed.
  • Its conclusions are inaccurate.
  • You can forget the headlines.

However, the study does illustrate the difficulty in proving diet-ADHD interactions. The truth is ADHD is a complex condition. It is affected by genetics, environment, family interactions, and food.

There are multiple nutritional approaches that reduce ADHD symptoms. The catch is each nutritional intervention only works for some children. Parents need to be willing to find what works best for their child by trial and error. Here are some of the nutritional approaches that have merit:

  • Eliminate food additives.
  • Add omega-3s.
  • Add a children’s multivitamin.
  • Eliminate added sugars.
  • Eat a healthy diet.
  • Eliminate food sensitivities.

For more details 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.

Are ADHD Symptoms Reduced by Omega-3s?

Written by Dr. Steve Chaney on . Posted in ADHD Diet, ADHD Symptoms and Omega-3s, omega-3s in young adults

Can Natural Approaches Cure ADHD?

Author: Dr. Stephen Chaney

 

adhd symptoms childrenYou keep seeing headlines saying that omega-3 fatty acids can help children with ADHD. But your pediatrician doesn’t recommend them. Why not? Is the story about omega-3s helping with ADHD symptoms just another myth created by supplement companies wanting to lighten your wallet? Or, is your doctor not keeping up with the latest scientific advances? As usual, the truth lies somewhere in between.

This week I will discuss the latest study (J.P-C. Chang et al, Neuropyschopharmacology, 43: 534-545, 2018) on omega-3s and ADHD symptoms. It provides an excellent update on the role of omega-3s in reducing ADHD symptoms.

 

How Was The Study Done?

adhd symptoms studyThe study was a meta-analysis. Meta-analyses combine the data from multiple studies. Their strength comes from the fact that they include data from subjects of different backgrounds and ethnicity. However, a meta-analysis can never be stronger than the studies it includes in its analysis. Simply put, if it combines data from poorly designed studies, it is no better than the weakest study.

The problem is that there have been a lot of poorly designed studies in this area of research. Some studies have included both children and adults. Others included subjects with psychiatric diagnoses other than ADHD. Still others combined omega-3 supplementation with other vitamins and nutrients. Finally, some used inadequate measures of ADHD symptoms and cognitive function. Because the design of previous studies has been so varied, the results have been conflicting. Some studies have found that omega-3 supplementation reduced ADHD symptoms. Others found no benefit.

Because of the confusion arising from poorly designed studies, the authors of this study applied very rigorous criteria in selecting the studies to be included in their meta-analysis. Their criteria were:

  • The studies were randomized, double-blind, placebo-controlled trials of mega-3 supplementation with DHA or EPA alone or in combination.
  • Participants were school-aged children (4-12 years) and adolescents (13-17 years) who had a diagnosis of ADHD.
  • The study measured clinical symptoms of ADHD as reported by parents. Some also included reports by teachers. When cognitive data were included, the studies relied on well-established cognitive tests.
  • The data allowed a calculation of effect size (this is a statistical requirement that simply says the quality of the data were good enough to reliably calculate the difference between the supplemented and control groups).
  • The publications were in peer reviewed journals.

They ended up with seven studies with a total of 534 subjects (318 received omega-3s and 216 received a placebo).

They also performed a separate metanalysis of studies that have measured omega-3 levels in school-aged children and adolescents who had been diagnosed with ADHD. The criteria for inclusion in this metanalysis were similarly rigorous. They ended up including nine studies totaling 558 subjects, 297 with ADHD and 261 controls in this meta-analysis.

 

Do Omega-3s Reduce ADHD Symptoms?

adhd symptoms omega-3sThe results from the first meta-analysis were:

  • Omega-3 supplementation significantly improved parental reports of total ADHD symptoms scores as well as scores of inattention and hyperactivity.
  • When the children were given cognitive performance tests, the omega-3 supplemented group performed better than the placebo group when tested for omission errors (for example, a number or word left out in a memory test) and commission errors (an incorrect number or word in a memory test).
  • A dose of EPA + DHA of 500 mg/day or greater appeared to be optimal.

The results from the second meta-analysis were:

  • Children and adolescents with ADHD had significantly lower levels of DHA, EPA, and total omega-3s in their red blood cells (a good measure of omega-3 status) than controls.

The authors concluded: “In summary, there is evidence that omega-3 supplementation improves clinical symptoms and cognitive performances in children and adolescents with ADHD, and that these youth have a deficiency of omega-3 levels. Our findings provide further support to the rationale for using omega-3s as a treatment option for ADHD.”

The authors went on to say: “In the context of ‘personalized medicine,’ it is tempting to speculate that a subpopulation of youth with ADHD and low levels of omega-3s may respond better to omega-3 supplementation, but there are no studies to date attempting this stratification approach [looking at the effect of omega-3 supplementation in the subpopulation with both ADHD and omega-3 deficiency]…Therefore, stratification of ADHD children by omega-3 levels…could be one approach to optimize the therapeutic effects of omega-3 supplementation.”

Basically, they are suggesting that the benefits of omega-3 supplementation are likely to be greatest for those children with ADHD who are also omega-3 deficient. They are also saying that future studies should measure omega-3 status before and after supplementation so that the true benefit of omega-3 supplementation can be determined. I agree

 

What Does This Mean For You?

adhd symptoms youthThis study was very well done. By including only the best designed studies in their meta-analysis, the authors have provided good evidence that omega-3s can be of benefit in reducing ADHD symptoms. The authors also pointed out that low-dose omega-3 supplementation is virtually free of side effects. Thus, this is an option that should be tried first, before considering medications to control ADHD symptoms.

On the other hand, I wouldn’t expect miracles. This was not a huge effect. Not all the ADHD symptoms improved with omega-3 supplementation. Teacher’s reports did not show the same benefits as parent’s reports.

There are two ways to interpret the limitations of omega-3 benefits seen in this meta-analysis.

  • Clinical studies report the average results for all the children in the study. Your child may not be average. If your child doesn’t like fish, especially the oil, cold-water fish that are rich in omega-3s, they may experience a greater benefit from omega-3 supplementation.
  • The benefit of omega-3s seen in this meta-analysis is just one facet of a holistic, natural approach for controlling ADHD without drugs. One of the best reviews on natural approaches for controlling ADHD was written by two pediatricians with years of experience dealing with ADHD. I wrote about their review in a previous issue, adhd diet vs medication, of “Health Tips From the Professor”. You should check it out. There was a lot of wisdom in their advice.

 

The Bottom Line

 

  • A recent meta-analysis has reported that omega-3 supplementation improves clinical symptoms and cognitive performances in children and adolescents with ADHD.
  • The optimal dose appeared to be 500 mg/day or above.
  • The authors also reported that children with ADHD were more likely to be omega-3 deficient than children without ADHD and suggested that omega-3 supplementation is most likely to be effective for those children who are omega-3 deficient.
  • The authors also pointed out that low-dose omega-3 supplementation had negligible side-effects, so it should be tried before the child is put on medication.
  • Omega-3s are just one facet of a holistic, natural approach for reducing ADHD symptoms.

For more details, 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.

Does Diet for Children with ADHD Matter?

Written by Dr. Steve Chaney on . Posted in ADHD Diet

Could A Healthy Diet Help Your Child?

Author: Dr. Stephen Chaney

 

diet for children with adhdDoes diet for children with ADHD matter?

The prevalence of ADHD appears to be skyrocketing. It increased by 42% in just 8 years between 2003 and 2011. Currently, 4.5 million children in the US are on ADHD medication, at a cost to taxpayers of $45 billion.

Unfortunately, ADHD medications come with serious side effects like loss of appetite and delayed growth, sleep disorders, nausea & stomach pains, headaches, moodiness and irritability. Even more worrisome is that many children say they “just don’t feel right” while they are on the drugs. Finally, there is the unintended message we are sending our children that drugs are the solution to their problems.

It is no wonder that millions of parents are looking for more natural solutions for their child’s ADHD. That is why recent headlines like “The Mediterranean Diet Could Help Children with ADHD” generate such interest.

In this issue of Health Tips From the Professor I have looked at the studies behind the headlines to answer your most pressing questions:

  • Would something as simple as the Mediterranean diet help my child control their ADHD symptoms?
  • Do they have to adhere to the Mediterranean diet, or would other healthy diets work just as well?

Answering these questions will tell us if diet for children with ADHD matters.

adhd dietHow Was The Study Designed?

The study behind the headlines (A Rios-Hernandez et al, Pediatrics DOI: 10.1542/peds.2016-2027) looked at 60 children and adolescents (ages 6-16) from southern Spain who were newly diagnosed with ADHD and compared them with 60 sex- and age-matched controls without ADHD from the same schools.

A food frequency questionnaire was administered by a trained interviewer and a scoring system called KIDMED was used to evaluate adherence to a Mediterranean-type diet. The study excluded children with more severe psychological problems and any children taking ADHD medications or nutritional supplements.

Does Diet for Children with ADHD Matter?

 

  • In a preliminary analysis of the data, the investigators discovered:
    • Breastfeeding was associated with decreased risk of ADHD.
    • Inactivity was associated with increased risk of ADHD.
    • Obesity was associated with increased risk of ADHD.

    child adhd dietOf course, the main point of the study was to investigate whether adherence to a Mediterranean-type diet influenced the risk of developing ADHD. The answer to this question was clear cut.

    • Adherence to a Mediterranean-type diet significantly reduced the risk of ADHD in both children and adolescents.

    So, clearly diet for children with ADHD does matter.

    Next, the investigators used the data obtained from the food frequency questionnaires to ask what components of a Mediterranean diet were most influential in reducing the risk of developing ADHD. These results were also very interesting:

    Dietary components that decreased the risk of ADHD included:

    • Consuming two or more servings of fruit every day (In Spain, the extra servings of fruit were primarily citrus, but presumably other fruits would be just as effective).
    • Consuming fresh or cooked vegetables more than once a day.
    • Consuming fatty fish on a regular basis (2-3 times a week).
    • Consuming grains or rice almost every day.
    • Starting the day with a healthy breakfast.

    Dietary components that increased the risk of ADHD included:

    • Eating at fast food restaurants more than once a week.
    • Skipping breakfast.
    • High consumption of soft drinks.
    • High consumption of candy and sugar.

    What Does This Mean For You?

    foods adhd dietThis study clearly showed that adherence to a Mediterranean diet is associated with a significantly lower incidence of ADHD.

    Of course, this study was conducted in southern Spain where a healthy diet is the Mediterranean diet. The question for people in other parts of the world is whether other healthy diets would work just as well.

    Based on their detailed study of the effect of individual dietary components, it is reasonable to assume that any healthy diet that…

    …emphasized fresh fruits & vegetables, whole grains, omega-3-rich fish, and…

    …started the day with a healthy breakfast, and…

    …minimized (or eliminated) fast foods, sodas, candy & other sweets…

    …would reduce the risk of ADHD.

    Plus, this is an approach that has no side effects. Just side benefits.

    Finally, if you read the study carefully, it is clear a holistic approach is always best. For example:

    • Individual dietary components had small effects on ADHD symptoms.
    • When those individual components were combined into a healthy diet, a major reduction in ADHD symptoms was observed.
    • The study suggested that reduction in ADHD symptoms would be even greater with a healthy lifestyle that included regular exercise and weight control.
    • The authors stated that supplementation could also play a role in reducing ADHD symptoms. They felt the best evidence was for supplementation with omega-3 fatty acids and a multivitamin multimineral supplement.

We can certainly conclude that diet for children with ADHD matters.

 

The Bottom Line

 

A recent study in southern Spain has looked at the relationship between adherence to a healthy Mediterranean diet and the risk of developing ADHD symptoms in children and adolescents.

  • In a preliminary analysis of the data, the investigators discovered:
    • Breastfeeding was associated with decreased risk of ADHD.
    • Inactivity was associated with increased risk of ADHD.
    • Obesity was associated with increased risk of ADHD.
  • These factors were independent of adherence to a Mediterranean diet.
  • Adherence to a Mediterranean-type diet significantly reduced the risk of ADHD in both children and adolescents. This was the major finding of the study.
  • The dietary components in the study that decreased the risk of ADHD were:
    • Consuming two or more servings of fruit every day (In Spain, the extra servings of fruit were primarily citrus, but presumably other fruits would be just as effective).
    • Consuming fresh or cooked vegetables more than once a day.
    • Consuming fatty fish on a regular basis (2-3 times a week).
    • Consuming grains or rice almost every day.
    • Starting the day with a healthy breakfast.
  • The dietary components that increased the risk of ADHD were:
    • Eating at fast food restaurants more than once a week.
    • Skipping breakfast.
    • High consumption of soft drinks.
    • High consumption of candy and sugar.
  • Based on their detailed study of the effect of individual dietary components, it is reasonable to assume that any healthy diet that…
    • …emphasized fresh fruits & vegetables, whole grains, omega-3-rich fish, and…
    • …started the day with a healthy breakfast, and…
    • …minimized (or eliminated) fast foods, sodas, candy & other sweets……would reduce the risk of ADHD.
  • Plus, this is an approach that has no side effects. Just side benefits.
  • Finally, if you read the study carefully, it is clear a holistic approach is always best. That would include:
    • A healthy diet
    • regular exercise and weight control.
    • Supplementation with omega-3 fatty acids and a multivitamin multimineral supplement.

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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