Category Archives: Diet

Why Fiber is Good For You

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Dieticians have maintained that fiber (typically from fruits and vegetables) is an essential part of our diet, and that a high-fiber diet has many health benefits, including lower risk for developing coronary heart disease, stroke, hypertension, diabetes, obesity, as well as lowering blood pressure and serum cholesterol levels (Health benefits of dietary fiber). Now evidence is coming in as to why that is the case: fiber (that resists digestion by the body’s digestive system) is readily eaten by bacteria in the gut — fiber feeds the gut’s microbiome. Keeping the microbiome in good shape is essential for the proper functioning of the gut.

Here are two media article discussing both studies (which were carried out with mice, but will apply to human systems too):
Fiber Is Good for You. Now Scientists May Know Why.

PSA from your gut microbes: Enjoy the holidays, but don’t forget your fiber

And here are the two original studies:
Bifidobacteria or Fiber Protects against Diet-Induced Microbiota-Mediated Colonic Mucus Deterioration

Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health

All four links have been added to Aging and Health > Diet.

Category: Aging, Diet

Alzheimer’s Linked To Sugar & Diabetes

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A new longitudinal investigation studied 5,189 people over 10 years. It found that people with high blood sugar had a faster rate of cognitive decline than those with normal blood sugar. This was true whether or not their blood-sugar level technically made them diabetic. In other words, the higher the blood sugar, the faster the cognitive decline.

Below are three media articles about the study:
The Startling Link Between Sugar and Alzheimer’s
Faster Cognitive Decline Tied to Hyperglycemia
Diabetes link to long-term mental decline

And here is a link to the formal study itself:
HbA1c, diabetes and cognitive decline: the English Longitudinal Study of Ageing

These four links have all been added to Health > Diet and Alzheimer’s > Risk Factors.

Category: Diet, Risk Factors

Eating Green For Brain (And Eye) Health

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The drumbeat of studies demonstrating the value of appropriate diet in managing brain health and resisting cognitive decline continues. Not long after this summer’s report Mediterranean/MIND Diet Seriously Fights Alzheimer’s/Dementia” comes a new study showing that sufficient consumption of green leafy vegetables might help slow mental decline so that you might have a mental age 11 years younger than you would otherwise. An added benefit is that a diet high in natural vitamin C, which includes green leafy vegetables, can lower the risk of cataracts in your eyes as you age by at least 20%, as seen in a another new study.

The green-leafy-vegetables-dementia study utilized 960 people (average age 81) from the Memory and Aging Project (MAP). The participants self-reported their eating habits on the Food Frequency Questionnaire (FFQ), and their thinking and memory skills were tested annually over an average of almost 5 years. From the FFQs, the researchers recorded the number of servings of spinach (½ cup cooked), kale/collard-greens (½ cup cooked), and lettuce salad (1 cup raw). Those whose intake of these vegetables was in the highest quintile (median 1.3 servings/day) had a cognitive decline rate that was equivalent to being 11 years younger in age.

The vitamin-C-cataract study showed that a healthy diet high in vitamin C obtained from fruits and vegetables can help slow or prevent the the development of cataracts regardless of genetic predisposition. The study utilized 1,000 pairs of female twins from the UK Twins registry. They filled out a detailed food questionnaire that measured their day-to-day nutrient intake when they were about 60 years old. Each participant’s eyes were digitally scanned to measure their initial progression of cataracts. Those whose diet included natural vitamin C obtained from roughly two servings of fruit and vegetables daily were 20% less likely to have developed cataracts than those who ate a less nutritious diet.

Ten years later, the study examined 324 of the twin pairs. Those who had originally reported eating more vitamin C in their diet were now at a 33% lower risk of developing cataracts compared to those who had eaten less vitamin C.

Unfortunately, popping vitamin C capsules won’t do the job. Those who reaped the greatest protective benefits had been steadily eating at least twice the recommended daily allowance of fruits and veggies, which is 75 milligrams for women and 90 milligrams for men. The study leader said: “We found no beneficial effect from supplements, only from the vitamin C in the diet. This probably means that it is not just vitamin C but everything about a healthy diet that is good for us and good for aging.” Consider regularly eating foods like oranges, red and green bell peppers, cantaloupe, papaya, kiwi, broccoli, and dark leafy greens.

Here are four media articles on the green-leafy-vegetables-dementia study:
Eat your vegetables: Nutrients in leafy greens may help prevent dementia
Cognitive Benefits Seen With Leafy Green Vegetable Intake
A Salad a Day May Be Good for Brain Health [Possible paywall]
Daily Serving of Leafy Greens May Boost Brain Health

And here is the original green-leafy-vegetables-dementia study article:
Nutrients and bioactive in green leafy vegetables and cognitive decline

Here are two media articles on the vitamin-C-cataract study article:
A Healthy Diet Rich In Vitamin C May Lower Risk Of Cataracts By 20%
Increased vitamin C in the diet could help protect against cataracts

And here is the original vitamin-C-cataract study article:
Genetic and Dietary Factors Influencing the Progression of Nuclear Cataract

All eight links have been added to Health > Diet.

Category: Diet

Adherence To A Diet — What Does It Mean?

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Hard on the heels of studies showing that following the Mediterranean diet (MD) or MIND diet can have significant effects on the likelihood of dementia as one ages, comes a very large-scale study showing that the fine-grain details of following the MD can significantly affect the cardiovascular outcomes for an individual as he/she ages, and so, presumably, also the brain health outcomes. At the simplest, “MD is associated with lower CVD [cardiovascular disease] risk but this relationship is confined to higher socioeconomic groups.” Since the MIND diet is quite similar to the the MD diet, presumably these results will also apply to it.

It has been informally obvious for some time that healthy eating focusing on quality vegetables is seriously sensitive to the price of those vegetables: Just perform a search on “health effects of the cost of fresh vegetables” and browse the results. However, the study in question, High adherence to the Mediterranean diet is associated with cardiovascular protection in higher but not in lower socioeconomic groups… set out to scientifically study the issue and quantify the relationship.

The Background statement for the study is:

It is uncertain whether the cardiovascular benefits associated with Mediterranean diet (MD) may differ across socioeconomic groups.

The study, conducted in Italy, enrolled 18,991 men and women aged 35 years and older from the Molise region and ran for 4.3 years. The degree of adherence to the Mediterranean Diet was was determined by the (self-reported) Mediterranean diet score (9-question version; see also 14-question version). Socioeconomic status (group) was determined by the household income (euros/year) combined with educational level. The individual cardiovascular hazard ratios (risk of heart attack) were calculated by standard statistical techniques).

This study reconfirmed earlier work that the Mediterranean diet (MD) is associated with lower cardiovascular disease (CVD) risk. However, it showed that amount of protection provided is sensitive to the socioeconomic status (group) of an individual. Specifically, for higher socioeconomic groups, an increase in the MD score was associated with an increase in protection from CVD risk, but that association was notably weaker for lower socioeconomic groups. Examination of the details of the study inputs showed that for each given MD score group, the socioeconomic subgroups of that score group showed many diet-related disparities such as dietary diversity and different intakes of antioxidants and polyphenols, organic vegetables and whole grain bread consumption.

To a certain extent, this shows that the Mediterranean diet score (MD score) is a blunt instrument. People attaining the same MD score can have such different dietary details that the associated CVD risk protection is significantly different. Since this effect appears independently for education and for income, it is not totally a matter of money, but also education and point of view.

This Moli-sani Project study focused on the MD and protection from CVD. However, the accumulation of findings culminating in Mediterranean/MIND Diet Seriously Fights Alzheimer’s/Dementia showed that the MD diet can provide protections against dementia. It would seem likely that the finds of the present study would also apply to dementia. Hopefully, the Moli-sani Project will have data available to explore this question too.

Several media articles about the study are given below. Unfortunately, they have taken a sensationalistic approach to their headlines, which imply that the MD won’t/cannot benefit someone who isn’t upper class. Clearly someone who is not upper class, but who devotes the same level of attention to diet (and a greater proportion of income) will statistically see similar benefits.

Here are two of the media article links together with a link to the study:

The Mediterranean diet doesn’t benefit everyone, study says

Health benefits of the Mediterranean diet are confirmed, but just for the upper class

Published research:
High adherence to the Mediterranean diet is associated with cardiovascular protection in higher but not in lower socioeconomic groups…

All the links have been added to Health > Diet.

Category: Diet

Mediterranean/MIND Diet Seriously Fights Alzheimer’s/Dementia

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Striking findings from two large-scale studies and two smaller studies show that following the Mediterranean diet or the related MIND diet can reduce the risk of dementia by one-third! The studies were reported at the recent 2017 Alzheimer’s Association International Conference in London.

The first study (Neuroprotective Diets …. abstract, full text) looked at the eating habits of almost 6,000 older adults (average age of 68) enrolled in the Health and Retirement Study, sponsored by the U.S. National Institute on Aging. The study is representative of the total US population, and as such, the results are widely applicable to the general public. Specifically, following the Mediterranean or MIND diet in general leads to 30%–35% lower risk of cognitive impairment during aging. Especially notable is the fact that the benefits appear to be a ‘sliding scale:’ “The more people stayed on those diets, the better they functioned cognitively,” said lead researcher Claire McEvoy.

The second study (The Mind Diet and Incident Dementia, Findings from the Women’s Health Initiative Memory Study; sponsored by National Institutes on Aging) examined the MIND diet’s effectiveness for more than 7,000 women. Similar to the first study, women closely following the MIND guidelines were 34% less likely to develop Alzheimer’s disease, while those moderately following the guidelines were 21%–24% less likely to develop Alzheimer’s.

An important observation is that these diets were originally developed to help improve cardiovascular health. Thus, following these diets will provide potential protection for both brain and heart health.

The third study (from Sweden: Which Dietary Index May Predict Preserved Cognitive Function in Nordic Older Adults?) enrolled more than 2,000 people and found that those eating a healthy diet called the Nordic Prudent Dietary Pattern (a diet related to the Mediterranean and MIND diets) for more than six years experienced better brain health.

The fourth study looked at the problem in the opposite direction. It looked at 330 people (average age 80) who followed a dietary pattern encouraging inflammation (so a diet “opposite” to the Mediterranean/MIND diets). These people performed poorly on brain games, and MRI scans showed that they also had a smaller total volume of brain gray matter. So this study negatively corroborates the outcomes of the first 3 studies.

Here is the Alzheimer’s Association Press Release about the four studies:
Healthy Eating Habits May Preserve Cognitive Function And Reduce The Risk Of Dementia

And here are several media stories about the presentations:
Mediterranean style diet may prevent dementia
Mediterranean-style diet linked to lower risk of dementia
Fight Dementia With Food: Following A Mediterranean Diet May Improve Brain Health, Studies Suggest
A Healthy Diet May Help Ward Off Dementia
Could the Mediterranean Diet Help Fight Dementia? Here’s What We Know

All the links have been added to Health > Diet