Is Soda One of The Causes of Arthritis?

Written by Dr. Steve Chaney on . Posted in current health articles, Health Current Events, Healthy Lifestyle

is soda one of the causes of arthritis

Author: Dr. Stephen Chaney

 

Recently, I came across an article which claimed an association between soda and arthritis.  So, is soda one of the causes of arthritis?  In previous health tips from the professor I have shared that soda consumption can cause weight gain  and heart disease . As if that weren’t reason enough to avoid sodas, recent headlines suggest that sodas can also cause rheumatoid arthritis. That is a pretty strong claim, so let’s look at the study behind those headlines.

Do Sodas Cause Arthritis?

This study (Hu et al., American Journal of Clinical Nutrition, 100: 959-967, 2014) followed 79, 570 women enrolled in the first Nurse’s Health Study (NHS) and 107,330 women enrolled in the second Nurse’s Health Study (NHS II) – that’s a total of 186,900 women – for at least 20 years. The women were aged 25-55 at the beginning of the studies and 857 of them developed rheumatoid arthritis over the next 20+ years.

All of the participants in the study filled out a questionnaire covering medical history, lifestyle and chronic disease at entry into the study and every two years afterwards. Compliance to this protocol was >90%, which is excellent for this type of study. The results were pretty impressive:

· Women who consumed ≥ 1 serving of sugar sweetened soda/day had a 63% higher risk of developing rheumatoid arthritis compared to women who consumed no sugar sweetened soda or consumed < 1 serving/month.

· The association between sugar-sweetened soda consumption and rheumatoid arthritis was much stronger for late-onset rheumatoid arthritis than it was for early-onset rheumatoid arthritis. When the authors restricted their analysis to women who developed rheumatoid arthritis after age 50, consumption of sugar sweetened sodas was associated with a 2.64-fold higher risk of developing rheumatoid arthritis (That’s a 264% increase).

· The type of sugar did not appear to matter. Sodas sweetened with sucrose and high-fructose corn syrup were equally likely to increase the risk of rheumatoid arthritis.

· There was no association between diet soda consumption and rheumatoid arthritis.

 

What Are The Strengths and Weaknesses Of The Study?

Strengths of The Study: The strengths of the study are fairly obvious.

This was a very large study and the effects (64%) and (264%) were also large. Those aren’t trivial differences. The size of the study and the magnitude of the effects bolster confidence in the outcome of the study.

Weaknesses of The Study:

This type of study measures associations. It doesn’t prove cause and effect. Therefore, the headlines saying “Soda Consumption is Associated With Arthritis” are more accurate than those saying “Sodas May Cause Arthritis”.

In studies of this kind we can never be sure whether the variable that was measured (soda consumption in this case) was responsible for the outcome or whether it was some other variable that wasn’t measured that was responsible for the outcome. In particular, the women who developed rheumatoid arthritis were also more likely to:

arthritis· Have lower incomes.
· Exercise less.
· Have higher energy (calorie) intake.
· Have poorer diets.
· Take fewer multivitamins and other supplements.

The authors tried their best to compensate for these differences statistically, and the fact that the very large effects of soda consumption on rheumatoid arthritis occurrence were not significantly affected when these differences were taken into account adds confidence to their conclusions. However, it is never possible to exclude the possibility that some other variable they did not measure was responsible for the increase in rheumatoid arthritis.

Are Diet Sodas Off the Hook?  Or,could They Be One of The Causes of Arthritis?

Could diet sodas be one of the causes of arthritis?  This study showed no association between diet soda consumption and rheumatoid arthritis. Previous studies have suggested that diet sodas don’t increase the risk of heart disease to the same extent as sugar-sweetened sodas. Does that mean that you should just start drinking diet sodas rather than sugar sweetened sodas?

diet sodas and arthritisThe answer is probably not. As I have pointed out in an earlier issue of “Health Tips From the Professor” , and has been confirmed by a recent meta-analysis of 24 clinical studies (Miller and Perez, American Journal of Clinical Nutrition, 100: 765-777, 2014), double blind studies in which all other caloric intake is carefully controlled generally show that people tend to gain slightly less weight when consuming diet sodas than when consuming sugar sweetened sodas.

But in the real world, people consuming diet sodas are just as likely to be overweight as people consuming sugar sweetened sodas. People seem to compensate for the calories saved with diet sodas by consuming more Big Macs, Mrs. Fields cookies and extra large Stabucks Lattes. In the real world, water is the only non-caloric beverage that is actually associated with lower weight.

Is It Enough To Just Stop Drinking Sodas?

I have often paraphrased that famous line from Western movies: “Just put down that soda and back away, and nobody gets hurt”. But is it that simple? Can you prevent rheumatoid arthritis just by drinking less soda?

Once again, the answer is probably no. There are a number of factors that can increase your risk of developing rheumatoid arthritis. Experts will tell you that the causes of rheumatoid arthritis are largely unknown, but that genetic predisposition, smoking and excessive alcohol use can increase your risk.

However, because rheumatoid arthritis is an inflammatory disease I would add overweight; diets high in animal protein, saturated fats, trans fats and sugar; food allergies; gut health issues; stress & exhaustion and chronic infections – and lack of fresh fruits and vegetables, omega-3 fatty acids and regular exercise.

The clinical study I described above found that soda consumption was much more strongly associated with late onset rheumatoid arthritis than early onset rheumatoid arthritis. Based on those data I would speculate that early onset rheumatoid arthritis may be more strongly influenced by genetics and other lifestyle factors, whereas late onset rheumatoid arthritis may be more strongly influenced by sugar sweetened sodas and other sugary foods. Only time will tell if my hypothesis is true.

Is soda one of the causes of arthritis?

The Bottom Line:

1) A recent study reported that women who consume ≥ 1 serving of sugar sweetened soda/day have a 63% higher risk of developing rheumatoid arthritis compared to women who consume no sugar sweetened soda or consume < 1 serving/month.

2) The association between sugar-sweetened soda consumption and rheumatoid arthritis is much stronger for late-onset rheumatoid arthritis than for early-onset rheumatoid arthritis. For women who first develop rheumatoid arthritis after the age of 50, consumption of sugar sweetened sodas is associated with a 2.64-fold higher risk of developing rheumatoid arthritis (That’s a 264% increase).

3) The type of sugar does not appear to matter. Sodas sweetened with sucrose and high-fructose corn syrup are equally likely to increase the risk of rheumatoid arthritis.

4) There was no association between diet soda consumption and rheumatoid arthritis. However, this does not mean that diet sodas are a good thing. Consumption of diet sodas is just as likely to be associated with obesity as is consumption of sugar sweetened sodas, and some recent studies suggest that consumption of diet sodas is associated with high blood pressure.

5) This was a very large and well done study, but it only measures associations, not cause and effect. Further studies will be needed to confirm this observation. However, we already know that sodas are bad for us. This may be just one more reason to minimize our consumption of sodas.

6) We shouldn’t assume that we can prevent rheumatoid arthritis by simply cutting sodas out of our diet. Arthritis has multiple causes (see article above). We should aim for a healthier overall lifestyle if we wish to reduce our risk of developing rheumatoid arthritis and other diseases.

7) Osteoarthritis is much more common than rheumatoid arthritis. This study did not include women with osteoarthritis, so it is uncertain whether these results will apply to osteoarthritis as well.

8) Men are much less likely to develop rheumatoid arthritis than women, so it will be difficult to do a comparable study in men. However, it is likely that the same association between soda consumption and rheumatoid arthritis would be seen in men as well.

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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Comments (1)

  • Jame Thornburgh

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    Hi.
    Thought. this was an interesting. article science based. If one reads the doctor’s
    Credentials he appears to basse his articles in sceince nkot fads
    lovw you mom

    Reply

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Latest Article

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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