Can Milk Be Bad For You?

Written by Dr. Steve Chaney on . Posted in Uncategorized

is milk bad for youGot Milk? Maybe Not

Author: Dr. Stephen Chaney

 

 

You’ve probably seen the ads featuring your favorite celebrities sporting a white mustache and saying “Got milk?” Those ads all suggest that milk is essential for strong bones and a healthy body.

And you are probably aware of dietary recommendations from learned experts saying that you should be consuming at least 2-3 servings of milk every day – more if you’re over 65.

If so, you are probably really confused by the recent headlines saying things like: “Milk Consumption May Increase the Risk of Fractures” and “High Consumption of Milk May Increase Mortality Risk”.

Can milk be bad for you?

Before you pour all your milk down the drain and put Bessie the cow out to pasture, we should examine the study behind the headlines.

Does Milk Actually Increase Fracture Risk?

The study in question (Michaelsson et al, British Medical Journal, 2014; 349; g6015 doi: 10.1136/bmj.g6015) followed 61,433 Swedish women (aged 39-74) for an average of 20.2 years and 45,339 Swedish men (aged 45-79) for an average of 11.2 years. The women filled out two food frequency questionnaires, one at the beginning of the study and another approximately 10 years later. The men filled out one food frequency questionnaire at the beginning of the study.

Mortality and cause of death were obtained from the Swedish Cause of Death Registry. Bone fracture information was obtained from the Swedish National Patient Registry (In countries like Sweden big brother knows everything about you).

The results were pretty dramatic. When they compared women who were drinking three or more glasses of milk per day to women who drank less than one glass of milk a day, the highest level of milk consumption was associated with a:

• 93% increased risk of dying from all causes.
• 90% increased risk of dying from cardiovascular disease.
• 44% increased risk of dying from cancer.
• 16% increased risk of having a bone fracture of any kind.
• 60% increased risk of having a hip fracture.

In contrast, consumption of fermented milk products (cheeses, soured milk and yoghurt) was associated with a decreased risk of mortality and bone fracture in women (a 10-15% decrease in risk for every serving consumed).

What Are The Dangers of Drinking Milk?

The authors speculated that that the increased mortality and fracture risk was due to galactose (a sugar formed from lactose, the primary naturally occurring sugar in unfermented milk). Their argument supporting this hypothesis was four fold:

1) In our intestines lactose is split into two sugars, glucose and galactose.

2) In animal models (primarily mice and rats) lifelong consumption of galactose is associated with shortened lifespan caused by, among other things, oxidative damage and chronic inflammation.

3) There is a rare genetic disease called galactosemia in humans that is caused by the lack of a crucial enzyme required to metabolize galactose. Patients with this disease die at a very early age without treatment. Even with dietary restriction of galactose they experience oxidative damage, inflammation and an increased risk for chronic diseases, including osteoporosis.

4) In a subset of patients enrolled in this study, high milk consumption was associated with an increase in blood markers of oxidative stress and inflammation.

While the results seem clear and the hypothesis seems plausible, we should perhaps look at the limitations of the study before making significant dietary changes.

Limitations of the Study

There are a number of significant limitations to this study.

what are the dangers of drinking milk1) It simply measures associations, not cause and effect.

2) The statistics were not entirely consistent. For example, while consumption of three or more glasses of milk (average = 3.4 glasses/day) was associated with 90% increased risk of mortality and cardiovascular mortality in women, there was only a 15% increase in risk associated with every glass of milk consumed. 15%/glass times 3.4 glasses/day = 51% – not 90%. A little bit of higher math tell us that these numbers don’t quite add up.

3) In men the effects were much smaller to nonexistent. In men high milk consumption was associated with a 10% increased risk in overall mortality and a 16% increased risk cardiovascular mortality, but milk consumption had essentially no effect on cancer mortality, fracture risk or hip fracture risk.

4) The galactose hypothesis is interesting, but far from convincing. Mice and rats don’t necessarily metabolize galactose in the same way as humans. Furthermore, in humans galactosemia is a very rare disease, and there is currently no evidence that dietary galactose poses a problem for people without the genetic defect that causes galactosemia.

5) Most importantly, there have been a number of previous studies examining the effects of milk consumption on both fracture risk and mortality, and those studies have been remarkably inconsistent. Some show increased risk and others show decreased risk. Meta-analyses of all previous clinical studies have shown no significant association between milk consumption and mortality (American Journal of Clinical Nutrition, 93: 158-171, 2011) or hip fracture (Journal of Bone Mineral Research, 26: 833-839, 2011).

While some of the media articles were characterizing this study as ground-breaking and one that should lead to changes in dietary recommendations, the authors were far more cautious in their interpretation of the data. They said: “The results of this study should be interpreted cautiously given the observational design of our study. The findings merit independent replication before they can be used for dietary recommendations.” I agree.

Where Else Can You Find The Nutrients That Milk Provides?

In summary, there is no consistent evidence that milk consumption increases your risk of mortality and bone fractures. However, there is also no consistent evidence that milk consumption decreases your risk of mortality or fracture.

Since milk provides no proven benefit and may pose some risk many of you may be wondering where else you can get the nutrients that milk provides.

Milk is an excellent source of calcium, magnesium, vitamin D, protein and riboflavin. When you carefully evaluate alternative food sources for these nutrients you will quickly discover that your choices are not straight forward. You need to be a knowledgeable consumer and careful label reader. For example:

vitamin-C• Green leafy vegetables are a high in calcium, but many of them also contain oxalate, which chelates the calcium and reduces its bioavailability. In short, green leafy vegetables are a healthy source for some of the calcium we need for healthy bones, but they should not be our primary source because of the relatively low calcium bioavailability.

• Cheeses are an excellent source of calcium, but many cheeses are high in fat and sodium.

• Yoghurts and other fermented milk products are an excellent source of calcium, but many of them are high in added sugars and artificial ingredients, which I do not recommend (see my article “Do Artificial Colors Cause Hyperactivity?” (https://healthtipsfromtheprofessor.com/do-artificial-colors-cause-hyperactivity/).

• Tofu and tempeh provide only 1/3 to ½ the calcium found in milk and provide no vitamin D.

• “Milk substitutes” made from soy, rice or other sources are often high in added sugars and may not provide the same nutrient profile as real milk. You have to read the labels carefully.

• Calcium supplements are an excellent source of calcium, but they have been controversial in recent years (see my article “Does Calcium Increase Heart Attack Risk?” (https://healthtipsfromtheprofessor.com/calcium-supplements-increase-heart-attack-risk/). My take on the controversy is that the latest studies have shown fairly convincingly that calcium supplements do not increase heart attack risk. However, if there is any risk, it is associated with calcium supplements that were not designed properly for incorporation of calcium into bone. My recommendation is to only choose calcium supplements that have been clinically proven to increase bone density.

• Well designed protein supplements can also be a good source of calcium and vitamin D, but many of them contain artificial sweeteners, which I do not recommend (see my articles “Do Diet Sodas Make You Fat?” (https://healthtipsfromtheprofessor.com/do-diet-sodas-make-you-fat/), “Does Sugar Cause Heart Disease?” (https://healthtipsfromtheprofessor.com/does-sugar-cause-heart-disease/), and “Can Soft Drinks Cause Heart Disease?” (https://healthtipsfromtheprofessor.com/soft-drinks-and-heart-disease/).

The Bottom Line:

1) A recent study suggested that high milk consumption (> 3 glasses per day) in women might be associated with a:

• 93% increased risk of dying from all causes.
• 90% increased risk of dying from cardiovascular disease.
• 44% increased risk of dying from cancer.
• 16% increased risk of having a bone fracture of any kind.
• 60% increased risk of having a hip fracture.

2) That study has a number of limitations and is not consistent with previous studies. Even the authors of the study stated: “The results [of this study] should be interpreted cautiously…”

3) Previous studies looking at the association of milk consumption and both fractures and mortality have been inconsistent. Meta-analyses of all previous studies show no significant association between milk consumption and either fractures or mortality.

4) In short, there is no consistent evidence to support the recent headlines suggesting that milk consumption might increase your risk of mortality and bone fractures, but there is also no consistent evidence that milk consumption decreases your risk of mortality or fractures.

5) Since milk provides no proven benefits and might pose some risk, you may be asking where else you can find the nutrients that milk provides. While there are a number of other dietary sources of the calcium needed for strong bones, each of them has potential limitations (for details, see the article above). You have to be a knowledgeable consumer and careful label reader if you are looking for non-milk sources of calcium.

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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A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

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.

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