There are news today (USA Today, MinnPost) about a Mayo Clinic study pointing at a link between consuming carbs and developing Alzheimer’s disease. “A high-carbohydrate intake could be bad for you because carbohydrates impact your glucose and insulin metabolism,” says Roberts, the lead author of the study. Proponents of low-carbs diets jumped on this study to promote the benefits of their diets. However, this study is inconclusive in several aspects.
Firstly, This study only correlates the consumption of carbs and the development of Alzheimer’s disease, and its conclusions are not cause-and-effect. This means that the increased incidence of Alzheimer’s disease was observed with consuming more carbs, but it could have been caused by other factors. One of which being the quality of carbs.
Secondly, it has long been recognized that the over-consumption of simple carbs, such as high fructose corn syrup, commonly found in sweets, pastries, cereals, and countless processed food, is detrimental to health. A prime example is type 2 diabetes, a condition where body cells and tissues can’t absorb enough essential glucose (digested sugars) due to an abnormal insulin resistance condition (insulin is an essential pancreas hormone required for cells to absorb glucose). It’s a largely agreed that type 2 diabetes is triggered by a poor diet high in simple carbs and fat, and low in complex carbs and nutrients.
This is a sharp contrast to consuming complex carbs, as found in unprocessed (or minimally processed) food, such as grains, beans, vegetables and fruits, which are known to promote health. Studies are clear that a diet rich in such complex carbs, with little or no added fat, meat and diaries significantly help prevent type 2 diabetes and improve health.
Type 3 diabetes is now the expression used to identify the same condition – insulin resistance – when it applies to brain cells. By becoming insulin-resistant, brain cells can’t absorb glucose – their main source of energy – and starve to death, resulting in brain damage over time.
The Mayo Clinic study does not specify which carbs were predominantly consumed.
Thirdly, there are many other factors that influence the absorption of glucose, such as exercising which promotes it. The study does not mention the level of activity of the patients.
For these reasons, this study cannot be the basis for promoting low-carb diets of any kind, such as Atkins, Paleo, etc. Those diets are very popular in publicity and the news, being promoted by a powerful and greedy diet industry that is specifically targeting everyone concerned with their weight (that’s about all of us). But independent long-term studies are consistently denying their benefits.