Obesity, Inflammation and Cognitive Decline

The rate of cognitive decline with aging is quite variable. 

Identifying important components of this process is needed for developing interventions to reduce the burden of Alzheimer's and other dementias.

Excess inflammation has been linked to obesity as well as aging-related cognitive decline.

Archana Singh-Manoux and colleagues recently published a study of the association between blood markers of inflammation and cognitive decline.

This study used data from the U.K. Whitehall II cohort, a group of men and women between the ages of 35-55 at intake.

This cohort has now been studied over a 20 year follow up with interval assessments about every five years.

Two blood markers of inflammation were studied in this cohort: interleukin-6 (IL-6) and C-reactive protein (CRP).

The study found strong associations between both blood markers of inflammation and rates of obesity (BMI >30) in the chart shown here.

Cognitive decline was measured by decrease scores on the Minimental Status Exam and other neuropsychological tests during the follow up period.

The primary finding from the study was that elevated IL-6 levels but not CRP levels at baseline were associated with accelerated cognitive decline.

Subjects in the highest IL-6 blood level group showed an 85% increased rate in losing 3 or more points on the Minimental Status Exam.

The authors note there study does not prove causality between IL-6 levels and cognitive decline but that:

"Inflammation is likely to play a role because of its impact on cerebral small-vessel disease, which could lead to changes that affect cognitive ageing."

It is also possible, that some of the link between obesity and cognitive decline may be attributable to increased obesity-related inflammation.

The practical clinical potential would be to attempt to identify and reduce inflammation in those most at risk. Anti-inflammatory drugs such as naproxen (Aleve in U.S.) have not been generally effect in trials to reduce rates of Alzheimer's disease.

However, these trials have typically not targeted groups with the highest blood markers of inflammation.

Readers with more interest in this topic can access the free full-text manuscript by clicking on the link in the citation below.

Photo of great blue heron from South Padre Island, TX is from the author's files.

Chart is an original figure from data abstracted from the manuscript.

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Singh-Manoux A, Dugravot A, Brunner E, Kumari M, Shipley M, Elbaz A, & Kivimaki M (2014). Interleukin-6 and C-reactive protein as predictors of cognitive decline in late midlife. Neurology, 83 (6), 486-93 PMID: 24991031

Mediterranean Diet and Aging

There is a growing research body of evidence to support beneficial effects of a Mediterranean diet on brain health.

In previous posts I have reviewed research on the Mediterranean diet and:

Cognitive Decline

Alzheimer's Disease Prevention

A recent study adds an important element in potential mechanisms for the beneficial effects of the Mediterranean diet.

Marta Crous-Bou and colleauges from Harvard University and the University of Washington published a study of the Mediterranean diet and chromosome telomere length.

This analysis used the large Nurses' Health Study cohort, blood samples and dietary questionnaires. Blood samples were analyzed for chromosome telomere length.

Chromosome telomere length has emerged as a biomarker of aging. DNA chromosome telomere lengths decline with age and shortened telomere lengths are associated with shortened life expectancy. 

The natural process of telomere shortening appears accelerated by inflammation and may be modified by lifestyle behaviors including dietary composition.

In the current study, subjects regularly completed dietary questionnaires. These questionnaires were rated on compliance with the Mediterranean diet on nine variables:

1. Vegetables
2. Fruits
3. Nuts
4. Whole grains
5. Legumes
6. Fish
7. Monounsaturated fat to saturated fat ratio
8. Red meat consumption
9. Alcohol intake

Median values for variables 1-8 were identified and subjects received a score of 1 if they were above the median (below median for red meat consumption). One point was awarded for consuming between 5 and 15 grams of alcohol per day.

Telomere length shortening was associated with older age and heavier cigarette consumption history.

Subjects were grouped into quintiles (20%) groups from lowest to highest Mediterranean diet score.

After adjusting for confounding variables, telomere length was statistically linked to Mediterranean diet score. Those with higher ratings on Mediterranean diet had longer telomeres indicating better aging.

The highest quintile group reported the following mean daily servings for each category: Vegetables (4.3 servings per day), fruits (3.2), whole grains (2.1), fish (0.5), red meat (0.5), legumes (0.6) and nuts (0.5).

The authors note they were unable to identify any single variable that had a strong independent effect. The effect appeared to be a combined global effect of the Mediterranean diet score.

This is an important study because it adds evidence for a biological mechanism for some of the previously reported clinical advantages associated with a Mediterranean diet. 

However, this study is limited by being primarily cross-sectional in design. It does not inform on whether changing diet to a Mediterranean type reduces rate of telomere shortening. 

Readers with more interest in this research can access the free full-text manuscript by clicking on the citation link below.

Photo of foods highlighted in the Mediterranean diet is an original photo from my files.

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Crous-Bou M, Fung TT, Prescott J, Julin B, Du M, Sun Q, Rexrode KM, Hu FB, & De Vivo I (2014). Mediterranean diet and telomere length in Nurses' Health Study: population based cohort study. BMJ (Clinical research ed.), 349 PMID: 25467028

Color Your Plate Healthy

Paula S. Barry, MD

“Just because it’s cold outside it doesn’t mean you can’t continue eating fresh, healthy foods packed with nutrients. A variety of options of fresh produce are available at most grocery stores,” says Paula S. Barry, MD, a primary care physician at Penn Family and Internal Medicine Longwood.

It has been said the more shades of vegetables and fruits your meal includes the more nutrients you’re eating. With that in mind, let’s take a look at some of the most colorful and healthy “super foods.”

Citrus: Bright Yellows and Greens

Citrus fruits, which encompass the usual suspects - lemons, limes, oranges and grapefruits - aren’t just bright and cheerful looking; they also come with healthy benefits and are at their juiciest in the winter. Citrus fruits are loaded with vitamin C - one medium orange delivers more than 100 percent of your daily dose. In addition, studies have shown that nobiletin, a flavonoid extracted from tangerines, helps to prevent obesity and offers protection against type 2 diabetes.

Pomegranates: Ruby Reds

Pomegranates, which originated from Persia, have a juice rich in antioxidants - compounds that block the activity of other chemicals known as free radicals, which have the potential to cause cancer. Studies have shown that just a cup of pomegranate juice might help prevent free radicals from developing “bad” LDL cholesterol, in effect, lowering high cholesterol levels. It’s also been said that this red juice can lower high blood pressure and help reduce blockages (atherosclerosis) in the arteries of the heart.

Kale: Rich Greens

Dark leafy greens, such as kale flourish in the cold of winter. In fact, a frost has been known to sweeten the leaves of kale. These greens are particularly rich in vitamins A, C and K and are especially good for women of childbearing age. There’s just a little over 30 calories in one cup of raw kale which contains protein and Alpha-linolenic acid, an omega-3 fatty acid.

Potatoes: Creamy Purples, Reds, Oranges and White

Potatoes sometimes get shortchanged for being a white starch and thought to hold little to no nutritional value, like white rice or white bread. However, potatoes, especially sweet potatoes and russet (skin on) potatoes, are packed with a variety of vitamins, minerals and low sodium. They are a whole food that contain an excellent source of two immunity boosters - vitamins C and B6, delivering 25% and 29% of your daily needs per medium potato, respectively. They are also a good source of fiber and folic acid, which has been known to help in the prevention of heart disease and stroke, as well as memory loss, osteoporosis and sleep problems. Folic acid is especially important for women of childbearing age. Purple potatoes can add an especially nice accent color to your plate and have even more healthy nutrients. These include antioxidants that have been linked to lowering the risk of cancer, as well as reducing inflammation.

Squash – Vibrant Oranges and Yellows

Butternut, acorn, delicata and spaghetti squash are some of the most popular assortments of winter squash and they are all excellent choices in the cold season. Want to feel fuller with lower calories? One cup of cooked winter squash contains only 80 calories and is high in vitamins A and C, as well as being a good source of vitamins B6 and K, potassium and folate. These super foods are also packed with helpful antioxidants and omega-3s, not to mention elements for a strong immune system to help protect against colds and flu.

Dr. Barry adds, “Although many experts differ on what food is the most nutritious or has the most antioxidants and disease fighting capabilities, it is certain that eating a well-balanced diet with a variety of fruits and vegetables is important.” She reminds us, “Regular exercise, portion control, and getting your daily dose of these ‘super foods’ can help keep you in tip-top shape and ready for the warm weather that lies ahead.”

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