The Mindspan Diet
The Book Brigade talks to geneticist Preston Estep about eating for your brain.
Posted Sep 27, 2016
Data from populations that stave off cognitive aging suggest that the healthiest eating patterns for physical and mental longevity differ from the dietary recommendations given to Americans.
What is the most surprising thing you discovered about the brain’s needs with age?
The brain is damaged by typical iron levels, and this process is driven by standard dietary intakes governed by accepted recommendations.
Why do you contend that dietary iron is bad for the brain? How does it harm?
The evidence is multi-layered.
• Iron accumulates with time as a normal part of the aging process. Primary accumulation is in areas known to be associated with age-dependent neurodegeneration
• Iron is the most abundant and potent pro-oxidant in the body
• Because of routine iron loss through menstruation, women are protected against the negative effects of iron buildup until menopause, when iron begins to accumulate
• Iron overload leads to dysfunction of the brain and nervous system, as well as of other tissues.
• People with the longest lives and little dementia have low body iron stores.
• Very high iron (the disease called hemochromatosis) is very damaging, and people with the disease die from multiple maladies at younger ages. Even moderately high iron is associated with various pathological processes, including atherosclerosis, shortened telomeres, compromised immunity, increased inflammation, and more.
Why does iron nutrition become more problematic with age?
Ultimately, this is an evolutionary question. It becomes problematic because natural selection doesn’t protect our health once we are past reproductive age. At iron levels that seem safe up to ages of reproduction, damage and other pathological consequences of iron excess add up and begin to impair health only in later years.
What tipped you off that iron is not an unmitigated good-guy nutrient?
I saw increasing numbers of high-quality publications on the harmful effects of iron, from many areas of science, including molecular and genetic evidence, which I consider much stronger than epidemiology and association studies. Then I read a book by Eugene Weinberg on the many harmful aspects of iron. That led me to the work of many other scientists. Together, the evidence at this point is overwhelming.
Why are foods in the US fortified with iron? How did we get it so wrong?
Iron-deficiency anemia used to be a big problem in the US, and pre-Depression era data were used to estimate the magnitude of the problem going forward. However, after WWII, over nutrition became a bigger problem and iron excess a more likely outcome than iron-deficiency anemia. Countries that lead the world in mental and physical longevity eat large amounts of non-fortified, refined-grain products.
What do you consider the optimal blood levels of iron (hemoglobin measure)? Do we need to bring back leeches?
Hemoglobin is a poor overall proxy for body iron stores, although it is one important measure. Serum ferritin is a better and key measure of overall body iron stores, but others are important too.
You seem to be a big fan of refined carbohydrates, and especially pasta, just as many others consider them the villain in the American diet. Can you explain your thinking on this?
Japanese lead the world in mindspan—which is the length of time people live with intact cognition— followed closely by certain Mediterraneans, especially those in and around the Mediterranean rivieras, at the border between Italy and France. In Japan, the main source of dietary energy for generations has been, and still is, white rice. In the Mediterranean rivieras, the role is filled by refined semolina pasta. The other foods of these traditional dietary patterns allow the body to handle these carbs with ease and blunt any spikes in blood sugar. Mediterraneans also consume a fair amount of olive oil. It is notable that white rice, semolina pasta, and olive oil are extremely low in iron relative to their caloric content. Refined carbohydrates form the base of the true mindspan diet.
Do our nutritional needs change course or even reverse course as we age? Is there some nutritional turning point in our lives?
Yes, especially for women. Men accumulate iron gradually over time, but women begin to accumulate it much more rapidly after they cease regular iron loss through menstruation. They typically not only catch up with men, their body iron stores eventually surpass men’s and soon thereafter they also surpass men in their risk of dementia.
What is the most important point you want to get across?
Common genetic variants put most people at risk for dementia, but everyone’s risk can be reduced greatly through diet and other positive lifestyle changes. It is extremely important to take this seriously because the difference between people who live very long lives with intact cognition and those who live lives of typical length and with increasing impairment is enormous. In terms of quality years, the difference isn’t months or a year or two, the real difference can be measured in decades.
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The Mind Span Diet