Is Diet Soda Bad For You?

Written by Dr. Steve Chaney on . Posted in Diet Soda and Health

Do Diet Sodas Increase Your Risk Of Stroke?

Author: Dr. Stephen Chaney

diet soda badIs diet soda bad for you?  With over two third of Americans overweight or obese, it is clear that we are in a midst of an obesity epidemic. Multiple studies have shown that over consumption of sugar-sweetened beverages (soft drinks, energy drinks, and “fruit” juices that aren’t made from real fruit) are major drivers of the obesity epidemic. Because of these trends, many experts recommend substituting artificially sweetened beverages for sugar-sweetened beverages in the American diet.

Is that advice sound? Do diet sodas help prevent weight gain? Are they safe? The answers to those questions are not as clear as you might expect.

Do Diet Sodas Prevent Weight Gain?

diet soda make you fatThe answer to that question would seem to be a no-brainer. Substituting beverages with no calories for beverages with calories should lead to less weight gain. However, as I summarized in a previous “Health Tips From the Professor” article Do Diet Sodas Make You Fat, the answer is not clear at all. Some studies suggest that diet sodas help people lose weight. Other studies suggest diet sodas cause just as much weight gain as sugar-sweetened sodas.

With so much confusion in the literature, what should we believe? More importantly, what do the experts say? This January an international consortium of experts reviewed all of the pertinent literature and published a position paper on whether artificially sweetened beverages were of value in responding to the global obesity crisis (Borges et al, PLOS Medicine, DOI: 10.1371/journal.pmed.1002195).

These authors concluded:

  • “In summary, the available evidence…does not consistently demonstrate that artificially-sweetened beverages are effective for weight loss or preventing metabolic abnormalities [pre-diabetes and diabetes]. Evidence on the impact of artificially-sweetened beverages on child health is even more limited and inconclusive than in adults.”
  • “The absence of evidence to support the role of artificially sweetened beverages in preventing weight gain and the lack of studies on their long-term effects on health strengthen the position that artificially-sweetened beverages should not be promoted as part of a healthy diet.”

Is Diet Soda Bad For You?

diet soda strokeAs if the lack of proven efficacy weren’t bad enough, other studies suggest that diet sodas may also be bad for your health. In previous issues of “Health Tips From the Professor,” I have discussed other studies showing that diet sodas are just as likely as regular sodas to increase risk of diabetes Artificial Sweeteners and Diabetes and heart disease Soft Drinks and Heart Disease.

Even worse, a study published earlier this month (Pase et al, Stroke, DOI: 10.1161/STROKE.AHA.116.016027 ) concluded that diet sodas may significantly increase the risk of stroke and Alzheimer’s disease.

This study looked at 2888 participants of the Framingham Heart Study. The participants evaluated for risk of stroke had a mean age of 62 on enrollment. Those evaluated for risk of dementia had a mean age of 69 on enrollment. All subjects were followed for 10 years. Three food frequency questionnaires were administered during that 10-year period to evaluate consumption of diet and sugar-sweetened sodas. The results of the study were:

  • People consuming at least one diet soda per day over a 10-year period were 3X more likely to have a stroke or develop dementia (primarily Alzheimer’s disease) than people consuming no diet sodas.
  • No increased risk of stroke or dementia was seen for people consuming sugar-sweetened beverages. However, that does not mean that sugar-sweetened beverages are good for you. Previous studies have shown they increase the risk of obesity and diabetes.
  • When the data were corrected for hypertension, cardiovascular disease, and obesity (waist to hip ratio), diet sodas still increased the risk of having a stroke by 2.6-fold.
  • This is not the only study to show a link between diet sodas and stroke. Two other studies have come to the same conclusion, and in both of those studies the increased risk was also seen only with diet soda consumption, not with sugar-sweetened soda consumption.

The author of the study concluded by saying: “As the consumption of artificially sweetened soft drinks is increasing in our community, along with the prevalence of stroke and dementia, future research is needed to replicate our findings and to investigate the mechanisms underlying the reported association.”

I agree. Current evidence does not definitively prove that diet sodas cause stroke and Alzheimer’s, but these are life-changing adverse health outcomes. Further research to test this association is desperately needed to know whether or not diet soda is bad for you.

Are Diet Sodas Safe and Effective?

diet soda dangerousAs you might expect these studies have caused quite a bit of controversy. Some experts have embraced these studies and have concluded that health professionals should stop recommending diet sodas as a safe and effective alternative to sugar-sweetened sodas.
Others have been unwilling to change their recommendation of diet sodas for people who are obese and/or diabetic. Their rationale is 3-fold:

  • These studies merely show that diet soda consumption is associated with weight gain, diabetes, heart disease, stroke and Alzheimer’s. Association does not prove causation, so their viewpoint is that there is no conclusive proof that diet sodas cause weight gain and health risks.
  • The obesity epidemic is a major health crisis, and consumption of sugar-sweetened beverages plays an important role in weight gain.
  • They are convinced that most people are so addicted to the sweet taste of sugar that they would be unwilling to switch to calorie free options like water or herbal teas.

In short, they are desperately clinging to the hope that substituting diet sodas for sugar-sweetened sodas will put a dent in the obesity crises because they don’t believe there are any other viable options.

What Do These Studies Mean For You?

I side with those experts who have looked at the data from the opposite perspective and concluded there is no convincing evidence that diet sodas are either safe or effective.

If the conversation were just centered around weight gain, diabetes, and heart disease, this could be considered an academic discussion. One could argue that diet sodas might have some benefit, and, at the worst, would have the same health risks as the regular sodas they replaced.

However, the possibility that diet sodas may increase the risk of stroke and dementia is a game-changer in my mind. That’s because consumption of sugar-sweetened sodas does not appear to increase the risk of either stroke or dementia. If true, that means that substitution of diet sodas for sugar-sweetened sodas is not a neutral substitution. It could cause serious harm.

With no good evidence that diet sodas help people control weight and the possibility that they may have serious health risks, it is difficult to see how anyone in good conscience can continue to recommend diet sodas in place of regular sodas.

My recommendation is to substitute water and other unsweetened beverages for the sugar sweetened beverages you are currently consuming. If you crave the fizz of sodas, drink carbonated water. If you need more taste, try herbal teas or infuse water with slices of lemon, lime, or your favorite fruit. If you buy commercial brands of flavored water, check the labels carefully. They may contain sugars or artificial sweeteners. Those you want to avoid.

So, is diet soda bad for you?  Well, it’s not good for you.

The Bottom Line

  • This January an international consortium of experts reviewed all of the pertinent literature and concluded: “The available evidence…does not consistently demonstrate that artificially-sweetened beverages are effective for weight loss or preventing metabolic abnormalities. The absence of evidence to support the role of artificially sweetened beverages in preventing weight gain and the lack of studies on other long-term effects on health strengthen the position that artificially-sweetened beverages should not be promoted as part of a healthy diet.”
  • This April a study was published reporting that people consuming at least one diet soda per day over a 10-year period were 3X more likely to have a stroke or develop dementia (primarily Alzheimer’s disease) than people consuming no diet sodas. Two other studies on the effect of diet sodas on the risk of stroke have come to similar conclusions.
  • We cannot yet say definitively that diet sodas cause stroke and dementia. Further research is clearly needed to test these associations. However, at this point it is safe to say there is no convincing evidence that diet sodas are either safe or effective.
  • With no good evidence that diet sodas help people control weight and the possibility that they may have serious health risks, it is difficult to see how anyone in good conscience can continue to recommend diet sodas as a substitute for sugar-sweetened sodas.
  • My recommendation is to substitute water and other unsweetened beverages for the sugar sweetened beverages you are currently consuming. If you crave the fizz of sodas, drink carbonated water. If you need more taste, try herbal teas or infuse water with slices of lemon, lime, or your favorite fruit. If you buy commercial brands of flavored water, check the labels carefully. They may contain sugars or artificial sweeteners. Those you want to avoid.
  • For a more nuanced discussion of this issue, 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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Latest Article

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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