Diabetes+Diet Sodas: Confusing Cause and Effect

SCIENTISTS like to remind us not to confuse cause and effect. But they're not immune from making that mistake themselves. Last week, for example, the mass media reported a Harvard Universitystudy that has exonerated diet sodas and other artificially-sweetened beverages from previous studies linking their consumption to diabetes.

“This is such a great example of confusing cause and effect. It’s akin to saying ‘playing basketball makes you tall’ because height and basketball are correlated. Of course, the real answer is that taller people play basketball,” says Dr. Josh Bloom of the American Council on Science and Health.

(Courtesy: Chris Coombs)

The new study ‒ published in The American Journal of Clinical Nutrition ‒ indicates that the link is a result of other factors common to both diet soda drinkers and people with diabetes, including that they are more likely to be overweight. In other words, people who are already diabetic or overweight are drinking more diet soda for those very reasons.

The Harvard University researchers, who followed a large group of men for 20 years, found that drinking regular soda and other sugary drinks often meant a person was more likely to get diabetes, but that was not true of artificially-sweetened soft drinks, or coffee or tea. They found that men who drank the most sugar-sweetened beverages ‒ about one serving a day on average ‒ were 16 percent more likely to be diagnosed with diabetes than men who never drank those beverages. The link was mostly due to soda and other carbonated beverages, and drinking non-carbonated sugar-sweetened fruit drinks such as lemonade was not linked with a higher risk of diabetes.

When nothing else was accounted for, men who drank a lot of diet soda and other diet drinks were also more likely to get diabetes. But once researchers took into account men's weight, blood pressure, and cholesterol, those drinks were not related to diabetes risk.

Replacing sugary drinks with diet versions seems to be a safe and healthy alternative, the authors say. "There are multiple alternatives to regular soda," says Dr. Frank Hu, one of the study's authors, adding, “Diet soda is perhaps not the best alternative, but moderate consumption is not going to have appreciable harmful effects."

When asked to comment on the study, Dr. Rebecca Brown, an endocrinologist at the National Institutes of Health, who has studied artificial sweeteners but was not involved in the Harvard research, told Reuters Health: “People who are at risk for diabetes or obesity…those may be the people who are more likely to choose artificial sweeteners because they may be more likely to be dieting.”

Hu and his colleagues analyzed data from more than 40,000 men who were followed between 1986 and 2006. During that time, participants regularly filled out questionnaires on their medical status and dietary habits, including how many servings of regular and diet sodas and other drinks they consumed every week. About 7 percent of men reported that they were diagnosed with diabetes at some point during the study.

The study also found that drinking coffee on a daily basis ‒ both regular and decaffeinated ‒ was linked to a lower risk of diabetes. Researchers aren't sure why that is, but it could be due to antioxidants or vitamins and minerals in coffee, Hu said.

Brown said that while there are still some health concerns about artificial sweeteners, none have been proven. "I certainly think that we have better evidence that drinking sugar-sweetened beverages increases health risks," Brown said, adding, "Certainly, reducing sugar-sweetened beverage consumption by any means (including substitution with diet drinks) is probably a good thing."

Diabetic Diet: Having More Money Doesn’t Mean You Eat Better

You’d think that once you take the budget constraints off, people can eat better, but that isn’t always the case.

University of Alberta graduate student Denise Maxwell who studied the factors around whether people with Type 2 diabetes stick to their diets, specifically at the correlation between dietary habits and economic circumstances, found having more money doesn’t make you more careful about your diet.

Wise food choices are a foundation of diabetes treatment. Diabetes experts suggest meal plans that are flexible and take your lifestyle and other health needs into account

Edmonton, Canada residents who make more than $120,000 a year are actually eating worse than some of the city’s poorest citizens with an annual income of less than $25,000, according to the study.

Indeed, Maxwell’s thesis ‒ ‘Type 2 diabetes: Economics of Dietary Adherence’ ‒ reaffirms that people in low income brackets often struggle to afford healthy food, and that diets become healthier as incomes rise. That’s true up to a point, but then it goes down

In fact, Maxwell found that people eating the healthiest diets were actually spending less on food than those eating poorly. “The more you are spending on food, it seems the worse your diet quality is. Which seems, when you first think about it, that it doesn’t make any sense,” she said.

Maxwell said she was surprised to see that the improvement in diet only continued to a certain income level before starting to fall again. The highest quality diets were found in people that make about $60,000 a year, a population she said was eating lots of meat, vegetables and fruit, and less packaged, frozen and restaurant food. “After that, their diet goes down pretty fast, and it goes down quite far,” she said.

“It actually goes down further than people that are on a very low income, and that was the part that was surprising. The people that are at the lower income actually have a better diet than the people at the very high income level,” she said.

While the poor are limited by money, the rich are limited by time. Maxwell’ s findings show that people in the higher income bracket are working more, and are eating convenience foods and dining in restaurants because of time constraints. “But just because it costs more doesn’t mean it’s better for you,” she said.

Maxwell said the study shows the need to continue educating the poor about healthy and economic food options, and to begin educating the rich about preparing healthy meals quickly.

Based on a news report in the The Vancouver Sun

Fat Fathers Pass on Diabetes

It stands to reason that chubby mothers give birth to chubby babies. After all, they share food for the nine months before delivery.

But what about chubby fathers passing on the health consequences of their bad eating habits? Evidence that they do comes from an Australian study with rats showing that chubby fathers could be passing on diabetes to their offspring.

Male rats fed a high-fat diet and mated with healthy female rats went on to produce offspring that had trouble with blood-sugar levels even though the offspring were eating low-fat foods.

"I think what's really exciting about this work is what's novel about it," Margaret Morris said of the study she supervised at the University of New South Wales.

"This is the first report of non-genetic, intergenerational transmission of metabolic consequences of a high-fat diet from father to offspring."

Conventional thinking

Morris looked at fathers because their role has largely been ignored. After all, conventional thinking is that their role stops after they pass on the DNA in their sperm cells. Morris wanted to test this, believing that both mother and father play a role.

"There's no question that the role of the uterus during the development of the baby is important, but I think it's important to realise that the father can be having a non-genetic effect as well," she said.

The findings of the study, published in the US journal Nature, relate to rats but are very likely to hold true for humans as well.

"If it's true in the human, it really underlines the necessity for both parents to be approaching pregnancy in the best possible physical shape," Morris said.

The critical aspect of the study - the non-genetic transmission - is something that is not a big surprise to Diabetes Australia chief executive Greg Johnson. That genes play a part in the passing on of diabetes is a certainty but the role of environmental factors are not well understood.

"There are things that people can do to help reduce their risk of developing type-2 diabetes," Johnson said. "Most of those modifiable things that they can do relate to eating a good healthy balanced diet and maintaining good physical activity and exercise and a healthy body weight."

But, of course, we knew that; what we did not know - and still do not know for sure - is that a healthy diet and keeping in shape has consequences for a man's offspring as well as for himself.