Could High-Carb Diets Cause Alzheimers?

Science blog points to an article in the Journal of Alzheimer’s Disease [related BBC article] that suggests that Alzheimers results from neural tissue being unable to properly respond to or produce insulin. In effect, the researchers say, Alzheimers may be a form of diabetes.

If borne out, this research raises an interesting possibility: Could the increased rates of Alzheimers seen in recent decades result from the low-fat, high-carb diets used to treat heart disease in the elderly?

The researchers in the study used a drug to interrupt the ability of the brains of mice to properly use insulin. The mice developed Alzheimers-like damage as a result. The study outcome most closely mimics Type 2 diabetes which is caused by the cells of the body no longer responding to insulin’s signal to take up sugar from the bloodstream. This is termed insulin resistance.

The standard nutritional advice for the last 30 years for those with signs of heart disease has been to follow a low-fat, high-carbohydrate diet. Unfortunately, carbohydrates simply turn to sugar when eaten. Eating a potato or a cup of pasta has pretty much the same effect on blood-sugar levels as eating the same weight in table sugar.

Reduced calorie, low-fat diets have a positive impact on weight and diabetes. However, many people on low-fat diets simply substitute calories they once got from fat with calories from carbohydrates. They consume as many or more calories than before and they don’t lose weight. The increased blood sugar from the carbs causes increased insulin levels which can eventually cause insulin resistance.

I can’t help but wonder if in some cases the insulin resistance occurs in the brain and leads to Alzheimers. Be a bit of an oops for the medical community but it wouldn’t be the first time where focusing on treating one particular disease had an unintended consequence for another.

11 thoughts on “Could High-Carb Diets Cause Alzheimers?”

  1. Our local clinic recommends low carb, high protein diet for diabetes, type 2. (They were not enthusiastic about high fat, but didn’t see that as the problem.)

    My students, however, who take nutritiion courses do papers that seem inspoired by an Atkins as devil vision not unlike the ones who take sociology & see Sam Walton as the devil.

  2. Insulin acts mainly in the liver and the skeletal muscles. Brain tissue doesn’t need insulin to take up glucose, which is what the brain uses primarily for energy. It is probably the insulin-like growth factor (IGF) that’s involved. The two peptide hormones are similar chemically, but not identical; and they have similar, but not identical, biological effects.

    It takes several days of starvation for the brain to start using fatty acids as well as the glucose the liver makes from muscle protein catabolism, usually from the amino acid alanine.

    Apolipoprotein E contributes to Alzheimer’s. Yes, aluminum (aluminum is the third most common element in the crust after oxygen and silicon and is present in water naturally)was found as a constituent of the neural plaques seen in Alzheimer’s, but aluminum has not been definitively shown to be a causative agent, if I remember correctly.

    Actually, in Type 2 diabetes, the insulin resistance comes first at the receptor in muscle and liver tissue. Carb consumption doesn’t contribute to insulin resistance. Low carb consumption simply masks the presence of insulin resistance.

    In the end, it will not make that much difference health-wise. The hyping of harm from diets causes more harm than the diets do (within limits… a 1400 kcal diet is safer than a 1000 kcal diet; but even a 1400 kcal diet is unsafe if caloric expenditure is increased substantially. For most of us, a 1600 to 2400 kcal diet will maintain weight. Most of us don’t eat more than 2400 kcal; but most of us don’t burn 2400 kcal.

    The BMI is not a valid measure of obesity. It is weight/height^2. A 110 kg 1.8 m bodybuilder would be considered obese, even though his body fat percentage is 4%. A 75 kg 1.7 m man with a body fat percentage of 35% would be obese. The folks who are truly in trouble are as big around as they are tall.

    Atherosclerosis starts in your teens. Low LDL won’t keep you from developing atherosclerosis. Normal BP (90/60 to 135/85) won’t either. Low LDL and normal BP just slow the rate of atherosclerosis, which is caused by hydraulic stress at vessel branches, platelet stickiness, and inflammation.

    In other words, we are mortal man doomed to die. It is only a matter of when and how; and if you alter some of the hows, you simply enhance other hows.

  3. Mitch, I wouldn’t take my word, but I believe that they decided that accumulation of aluminum was a symptom and not a cause of alzheimers.

  4. Chel, I don’t know what Shannon thinks, but I tend to think of “meat-eating” as right and “tofu-eating” as left – but that’s probably silly association – I came from the reddest of states, both in terms of politics & meat.

    My students’ politics (even about Walton) wasn’t the point – it was that their classes simplified the teacher’s arguments; they set up villains they were likely to know and the “conventional wisdom” was repeated in my class with a certainty that a little research should have led them to qualify.

  5. The rationale behind Atkins and other low-carb regimens is quite simple. Mankind evolved on a diet that existed before modern agriculture- before processed sugar and flour became such a big part of our diets. That’s why obesity and diabetes are relatively modern diseases.

    Eat like a Caveman. Eat only what was available to early man: meat, fish and poultry; fruits and vegetables; nuts, eggs, and berries.

  6. Exactly, Barry! You posted my point!

    The positive population growth spurred by the introduction of sugary grains to our diet has allowed us to ignore their incompatibility with the chemistry of our animal. Evolution, I think, prepares the animal mostly for hardship, and leaves it poorly prepared for plenty.

    My Irish brother-in-law was just diagnosed as “whey intolerant.” No more frozen pizzas with their wheat-flour crusts – he’s returning to the potato.

    And here in Arizona, the epidemic of diabetes mellitus in the Navajo nation is spurring a search for other polysaccharide sources to replace the Old-world grass-seeds (wheat, oats, rye or rice) that appear to trigger the disease. To combat this diet-etic incompatibility, many are returning to traditional flours like ground Mesquite pods, pine, cactus and oak seeds.

  7. What’s wrong with bread? I like bread.

    BTW, what does whey have to do with pizza crust? Did you mean wheat?

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