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Nuts For Longevity: Daily Handful Is Linked To Longer Life : The Salt : NPR

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Nuts For Longevity: Daily Handful Is Linked To Longer Life : The Salt : NPR

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Americans have not always been in love with nuts.

Think about it: They're loaded with calories and fat. Plus, they can be expensive.

But Americans' views - and eating habits - when it comes to nuts are changing. Fast.

There's a growing body of scientific evidence that's putting a health halo over supermarkets' expanding nut aisles.

Earlier this year, a large diet study concluded that people who eat a Mediterranean-style diet supplemented with daily portions of nuts and olive oil have significantly lower risks of heart attacks and strokes.

And just last month, more evidence emerged that snacking on nuts helps control our appetites, which may stave off weight gain.

Now, a new study published in the New England Journal of Medicine finds that people in the habit of eating a daily handful (a 1-ounce serving) of nuts are more likely to live longer compared with people who rarely consume nuts.

"The preponderance of evidence suggests a health benefit [from eating nuts]," says researcher Charles Fuchs of the Dana-Farber Cancer Institute and Harvard Medical School.

To isolate the association between nut consumption and lifespan, Fuchs and his colleagues combined data from two long-term studies that include about 76,000 women and 42,000 men.

The participants in the study completed food frequency surveys every two to four years over several decades. They answered all kinds of questions about dozens of different kinds of foods, including how many servings of nuts they consumed.

"What we find is that regular nut consumers have about a 20 percent reduction in all-cause mortality" over the course of the study, Fuchs says. This includes lower death rates from heart disease and cancer.

Now, since death is inevitable for all of us, here's another way to think about the findings: Men and women who were regularly munching on peanuts or tree nuts like almonds, pecans and walnuts in their 30s and 40s when the study began were significantly more likely to reach their 70s, compared with folks who didn't eat nuts.

So how could a daily handful of nuts possibly be so beneficial? Fuchs says it's not entirely clear.

"What we think nuts do is that they affect metabolism," he explains. Prior research has shown that nuts help us feel fuller, faster. And nuts also help control blood sugar.

Fuchs says if nuts lead to a sense of satiety and help people eat less, many of the other benefits may follow. This could "reduce the risk of diabetes and also reduce the risk of cardiovascular disease," he says.

Of course, this study does not prove a cause and effect between eating nuts and living longer. The design of this type of long-term, observational study only enables researchers to establish an association - a link.

Going forward, researchers want to try to better understand what might explain this link. They want to know more about how the combination of beneficial plant compounds and minerals - such as magnesium, fiber and protein - found in nuts may be influencing the body.

With all the good news about nuts in the news, experts who track food trends say more Americans are eating them.

"Nuts are in the perfect spot right now," says John Frank of Mintel. The market research firm estimates that sales of nuts and dried fruit in the U.S. will grow from about $7 billion in annual sales in 2012 to over $9 billion by 2017.

Nuts check a lot of boxes that young adults are looking for: They're high in protein, they're easy to grab and eat on the go, and they're a natural, plant-based food.

"I'm a vegetarian, so nuts are an important part of my diet, for added protein," shopper Emily Williams told me as she added nuts to her shopping cart at a Trader Joe's in Washington, D.C.

Many grocery stores' expanding nut aisles now include lots of variety - everything from dark-chocolate-covered almonds to spicy, Asian-flavor-infused nuts.

And Frank says millennials love the variety. Young adults aren't just snacking on nuts - increasingly, they're tossing them in salads and sprinkling them in yogurt and cereal.

One note about the NEJM study on nuts: The major part of the study was funded by the National Institutes of Health. The researchers also accepted a grant from the International Tree Nut Council Nutrition Research and Education Foundation to cover the cost of analyzing the data.

"The [nut] council approved the grant without any knowledge of the results," says Fuchs. And there was an agreement that the researchers would have reported the findings no matter what the results showed.

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Nuts For Longevity: Daily Handful Is Linked To Longer Life

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Men and women who were regularly munching on peanuts or tree nuts in their 30s and 40s were significantly more likely to reach their 70s, a study found. Researchers say they aren't sure why nuts promote longevity, but they think it has to do with how they affect metabolism and satiety.

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For Mind And Body: Study Finds Mediterranean Diet Boosts Both : The Salt : NPR

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For Mind And Body: Study Finds Mediterranean Diet Boosts Both : The Salt : NPR

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For all of us nearing middle age, or slogging through it, yes, there is a benefit in eating a Mediterranean-style diet rich in fish, nuts, vegetables and fruit.

A new study published in the Annals of Internal Medicine finds that women who followed this pattern of eating in their 50s were about 40 percent more likely to reach the later decades without developing chronic diseases and memory or physical problems, compared to women who didn't eat as well.

Researchers tracked the dietary habits and lifestyles of more than 10,000 women, beginning in late middle age. Every two years, the women filled out detailed surveys describing their diets.

Over the next 15 years, researchers kept tabs on who among the women developed a whole host of chronic diseases including Parkinson's, cancer, and lung and pulmonary disease. The women were also given a battery of memory tests, and researchers also evaluated physical function, meaning the women's abilities to move around and stay active.

"This really suggests that a healthy diet can help improve multiple aspects of your health and your ability to function when you're older," says researcher Fran Grodstein of the Harvard School of Public Health.

Meir Stampfer, co-author of the new paper, says he was "surprised by the magnitude of the effects" in the study, given what we already know about the heart benefits of a Mediterranean style diet.

Stampfer says this study adds to a growing body of evidence that all points to measurable benefits of eating a diet that is rich in plant-based food and low in saturated fats, meat and refined starch. He says he's changed his own eating habits based on the weight of the evidence.

"I'm eating more nuts, berries and fruit," he says. As well as fewer potatoes, and less meat. "And I'm happier."

Yes, the evidence suggests that our diets really can help shape mood and overall well-being.
Making The Shift
Adopting a Mediterranean-style diet is not as difficult as you you might think. It's not a complete diet overhaul.

"Mediterranean cooking is simply a tweaking of basic cooking," says Chef Michael Friedman, part-owner of the Red Hen, a hip, newish restaurant in Washington, D.C.

Switching from butter to olive oil is the first step that any cook can make, Friedman says. After that, he says, think about scaling up vegetables, even ones you normally overlook.

The day I visited, Friedman whipped up a super creamy mushroom risotto topped with a parsnip puree. It sounds fancy, but Friedman says it's really pretty simple: You just roast the parsnips with thyme, garlic and a little salt, then put them in a blender.

"If you look at it, it has the texture of creaminess, of butter," he says. "But it's just a puree."

The taste is surprising.

Friedman agreed. There was no butter, no cream, no cheese, but the taste was divine. "I kind of tricked myself a little bit," he says.

Oh, and a bit of good news for those who like a nice glass of vino to accompany the meal. The healthy eaters in the study consumed moderate amounts of alcohol.

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For Mind And Body: Study Finds Mediterranean Diet Boosts Both

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A new study finds that women who followed a Mediterranean style of eating in their 50s were about 40 percent more likely to reach the later decades without developing chronic diseases and memory or physical problems, compared to women who didn't eat as well.

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Olive oil reduces oxidative stress

Olive oil and fish oil contain anti-inflammatory omega-3 fatty acids.

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There are many disagreements about fats in the diet.

However, pretty much everyone agrees that olive oil, especially extra virgin, is good for you.

Here are 11 health benefits of olive oil that are supported by scientific research.

Olive oil is the natural oil extracted from olives, the fatty fruit of the olive tree.

About 24% of the oil is saturated fats and omega-6 and omega-3 fatty acids ( 1).

But the predominant (73%) fatty acid in olive oil is a monounsaturated fat called oleic acid, which is extremely healthy.

Oleic acid is believed to help reduce inflammation, and may have beneficial effects on genes linked to cancer ( 2, 3, 4, 5).

Monounsaturated fats in extra virgin olive oil are also quite resistant to high heat, making it a healthy choice for cooking.

Bottom Line: Olive oil is rich in monounsaturated oleic acid. This fatty acid is believed to have many beneficial effects, and is a healthy choice for cooking.

Extra virgin olive oil is fairly nutritious.

Apart from its beneficial fatty acids, it contains modest amounts of Vitamins E and K.

But olive oil is also loaded with powerful antioxidants.

These antioxidants are biologically active and may help fight serious diseases ( 6, 7).

This includes antioxidants that can fight inflammation and help prevent the cholesterol in our blood from becoming oxidized, both crucial steps in the heart disease process ( 8, 9).

Bottom Line: Extra virgin olive oil is loaded with antioxidants, some of which have powerful biological effects.

Chronic inflammation is thought to be among the leading drivers of many diseases.

This includes cancer, cardiovascular disease, metabolic syndrome, diabetes, Alzheimer's, arthritis and even obesity.

Olive oil can reduce inflammation, which may be one of the main reasons for its health benefits.

The main anti-inflammatory effects are mediated by the antioxidants. Key among them is oleocanthal, which has been shown to work similarly to ibuprofen, an anti-inflammatory drug ( 10).

Some scientists estimate that the oleocanthal in 50 ml (3.4 tablespoons) of extra virgin olive oil has a similar effectiveness as 10% of the adult dosage of ibuprofen ( 11).

There are also studies suggesting that oleic acid itself, the main fatty acid in olive oil, can reduce levels of important inflammatory markers like CRP ( 2, 3).

One study also showed that olive oil antioxidants can inhibit some genes and proteins that drive inflammation ( 12).

Bottom Line: Olive oil contains nutrients that can fight inflammation. This includes oleic acid, as well as the antioxidant oleocanthal.

Stroke is caused by a disturbance of blood flow to the brain, either due to a blood clot or bleeding.

In developed nations, stroke is the second most common cause of death, right after heart disease ( 13).

The relationship between olive oil and the risk of stroke has been studied extensively.

A large review study that included over 841,000 subjects found that olive oil was the only source of monounsaturated fat associated with a reduced risk of stroke and heart disease ( 14).

These findings are supported by another large review study, this one with 140,000 participants. Researchers found that those who consumed olive oil were at a much lower risk of stroke ( 15).

Bottom Line: There are many large studies showing that people who consume olive oil have a much lower risk of developing stroke, the second biggest killer in developed countries.

Heart disease is the most common cause of death in the world ( 16).

Observational studies conducted a few decades ago showed that heart disease was rare around the Mediterranean Sea.

This led to extensive research on the Mediterranean diet, which has now been shown to significantly reduce the risk of heart disease ( 17, 18).

Extra virgin olive oil is one of the key features of this diet, and protects against heart disease via numerous mechanisms ( 19).

It lowers inflammation, protects LDL cholesterol from oxidation, improves the function of the lining of the blood vessels, and may help prevent unwanted blood clotting ( 20, 21, 22, 23, 24, 25).

Interestingly, it has also been shown to lower blood pressure, which is one of the strongest risk factors for heart disease and premature death. In one study, olive oil reduced the need for blood pressure meds by 48% ( 26, 27, 28).

The truth is that dozens, if not hundreds, of studies have shown that extra virgin olive oil has powerful benefits for the heart.

If you have heart disease, a family history of heart disease, or any other major risk factor, then you might want to consider including plenty of extra virgin olive oil in your diet.

Bottom Line: Olive oil has numerous benefits for heart health. It lowers blood pressure, protects LDL particles from oxidation, and has beneficial effects on many other risk factors.

Eating fat does not make you fat, and olive oil is no exception.

Numerous studies have linked Mediterranean dietary patterns, rich in olive oil, with favorable effects on body weight ( 29, 30, 31).

In a 2.5 year study of more than 7000 Spanish college students, consuming a lot of olive oil was not linked to increased weight ( 32).

In other words, high intake of olive oil is not linked with weight gain or obesity in observational studies.

A 3-year study in 187 participants found that a diet rich in olive oil increased levels of antioxidants in the blood and caused weight loss ( 33).

Bottom Line: Consuming large amounts of olive oil does not appear to increase the likelihood of weight gain. It may even be beneficial for weight loss.

Alzheimer's disease is the most common neurodegenerative disease in the world.

One of its key features is a buildup of so-called beta amyloid plaques inside brain cells.

One study in mice showed that a substance in olive oil can help remove these plaques from brain cells ( 34).

Another study, this time in humans, showed that a Mediterranean diet with olive oil had beneficial effects on brain function ( 35).

Bottom Line: Some studies suggest that olive oil can help fight Alzheimer's disease, but more research is needed to confirm this.

Olive oil appears to be highly protective against diabetes.

Several studies have linked olive oil to beneficial effects on blood sugar and insulin sensitivity ( 36, 37).

A randomized clinical trial of 418 non-diabetic participants recently confirmed the protective effects of olive oil ( 38).

In this study, a Mediterranean diet with olive oil reduced the risk of developing type 2 diabetes by over 40%.

Bottom Line: Both observational studies and clinical trials suggest that olive oil, combined with a Mediterranean diet, can reduce the risk of developing type 2 diabetes.

Cancer is one of the most common causes of death in the world.

People in Mediterranean countries have a lower risk of some cancers, and many researchers believe that olive oil may have something to do with it ( 39).

The antioxidants in olive oil can reduce oxidative damage due to free radicals, which is believed to be one of the leading drivers of cancer ( 40, 41).

Many test tube studies have shown that compounds in olive oil can help fight cancer cells ( 42, 43).

Whether olive oil can actually help to prevent cancer needs to be studied properly in humans.

Bottom Line: There is preliminary evidence that olive oil may help prevent cancer, but this needs to be studied properly.

Rheumatoid arthritis is an autoimmune disease characterized by deformed and painful joints.

The exact cause is not well understood, but it involves the body's immune system attacking normal cells by mistake.

Olive oil supplementation appears to improve inflammatory markers and reduce oxidative stress in individuals with rheumatoid arthritis ( 44, 45).

Olive oil appears to be particularly beneficial when combined with fish oil, a source of anti-inflammatory omega-3 fatty acids.

In one study, olive oil and fish oil significantly reduced joint pain, handgrip strength and morning stiffness in people with rheumatoid arthritis ( 46).

Bottom Line: Olive oil can help reduce joint pain and swelling from rheumatoid arthritis. The beneficial effects are greatly increased when combined with fish oil.

Olive oil contains many nutrients that can inhibit or kill harmful bacteria ( 47).

One of these is Helicobacter pylori, a bacteria that lives in the stomach and can cause stomach ulcers and stomach cancer.

Test tube studies have shown extra virgin olive oil to be effective against eight strains of this bacteria, three of which are resistant to antibiotics ( 48).

A study in humans showed that 30 grams of extra virgin olive oil can eliminate Helicobacter pylori infection in 10-40% of people in as little as 2 weeks ( 49).

Bottom Line: Extra virgin olive oil has anti-bacterial properties, and has been shown to be particularly effective against Helicobacter pylori, a type of bacteria that can cause stomach ulcers and stomach cancer.

The importance of getting the right kind of olive oil can not be overstated.

Extra virgin olive oil is the only type that contains all the antioxidants and bioactive compounds. It is the only olive oil we recommend.

But even so, there is a lot of fraud on the olive oil market, and many oils that have "extra virgin" on the label have been diluted with other refined oils.

Therefore, do some research and make sure that you're actually getting real extra virgin olive oil.

At the end of the day, quality extra virgin olive oil is super healthy.

It may just be the single healthiest fat on the planet.

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There are many disagreements about fats in the diet. However, pretty much everyone agrees that olive oil, especially extra virgin, is good for you. Here are 11 health benefits of olive oil that are supported by scientific research. Olive oil is the natural oil extracted from olives, the fatty fruit of the olive tree.

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Coach Mike's Report On Why The Mediterranean Diet- Is Ideal for Athletes

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Coach Mike's Report On Why The Mediterranean Diet- Is Ideal for Athletes

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Is a Mediterranean Diet Ideal for Athletes?

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Is the Mediterranean Diet Ideal for Athletes? Michael Stoick Concordia University, St. Paul KHS 605 Nutrition and Metabolism Cohort #307 Instructor Jason Ewoldt July 14, 2014 Is a Mediterranean Diet Ideal for Athletes? The Mediterranean diet is a sensibly balanced diet that is ...

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10 Things to Know About the Mediterranean Diet

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10 Things to Know About the Mediterranean Diet

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Everything you need to know about the Mediterranean diet. Lose weight, feel great, and improve your heart health by following the Mediterranean diet.

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U.S. News Health Report on The Mediterranean Diet

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U.S. News Health Report on The Mediterranean Diet

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Mediterranean diet improves sexual function in women with the metab... - PubMed - NCBI

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Mediterranean diet improves sexual function in women with the metab... - PubMed - NCBI

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Mediterranean diet improves sexual function in women with the metabolic syndrome. - PubMed - NCBI

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Int J Impot Res. 2007 Sep-Oct;19(5):486-91. Epub 2007 Aug 2. Randomized Controlled Trial; Research Support, Non-U.S. Gov't

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Mediterranean diet improves erectile function in subjects with the ... - PubMed - NCBI

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Mediterranean diet improves erectile function in subjects with the ... - PubMed - NCBI

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Mediterranean diet improves erectile function in subjects with the metabolic syndrome. - PubMed - NCBI

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Int J Impot Res. 2006 Jul-Aug;18(4):405-10. Epub 2006 Jan 5. Controlled Clinical Trial

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Mediterranean diet and telomere length in Nurses’ Health Study: population based cohort study | The BMJ

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Mediterranean diet and telomere length in Nurses’ Health Study: population based cohort study | The BMJ

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Study population

The Nurses' Health Study is a prospective cohort study of 121 700 female registered nurses in 11 US states, aged 30-55 years at enrollment. The study was established in 1976; since then, participants have completed biennial questionnaires to update information on demographic characteristics, lifestyle factors, and newly diagnosed diseases. 20 21 Between 1989 and 1990 32 825 cohort participants provided blood samples. Details of the blood collection and archival methods have been described previously. 22

Multiple nested case-control studies have been conducted within the Nurses' Health Study blood sub-cohort to investigate the association between leukocyte telomere length and cancer, cardiovascular disease, and cognitive function, among others. 23 24 25 26 27 28 The analysis reported here included data on 4676 women selected as healthy controls (free of major chronic diseases, including cancer and cardiovascular disease) from nested case-control studies, with previously measured leukocyte telomere length and completed food frequency questionnaires at the time of blood draw.

Dietary assessment

In 1980 participants completed a 61 item semi-quantitative food frequency questionnaire to assess their diet in the previous year. In 1984, 1986, and every four years thereafter, an expanded food frequency questionnaires containing 116-130 food items was sent to the nurses to update their dietary information. Participants were asked about the frequency of consumption of each food item of a pre-specified standard portion size in the previous year. The validity of these questionnaires has been previously described. 29 We calculated all dietary patterns and diet quality scores from self reported dietary data on the 1990 food frequency questionnaire, the closest to the blood draw (1989-90).

Trichopoulou adapted the Alternate Mediterranean Diet score from the Mediterranean Diet Score to assess adherence to the traditional Mediterranean diet. 2 The Alternate Mediterranean Diet score includes the following nine components: vegetables (excluding potatoes), fruits, nuts, whole grains, legumes, fish, monounsaturated:saturated fatty acid ratio, red and processed meats, and moderate alcohol intake. The possible score range is 0-9, with a higher score representing a closer resemblance to the Mediterranean diet. We dichotomized each of the nine dietary components at the median. We gave participants with intake above the median 1 point each for vegetables, fruits, nuts, whole grains, legumes, fish, and monounsaturated:saturated fatty acid ratio; we scored intake equal to or below the median as 0 points for each component. We scored red and processed meat consumption below the median as 1 point, with 0 points for intake equal to or above the median. Participants received 1 point for alcohol intake between 5 and 15 g/day; otherwise, they got 0 points. Details of the Alternate Mediterranean Diet scoring system are described elsewhere. 3

We used principal component analysis of the food frequency questionnaires to identify prudent and Western dietary patterns. 30 31 The prudent dietary pattern is characterized by high intakes of fruits, vegetables, legumes, fish and other seafood, poultry, and whole grains; the Western dietary pattern includes high intakes of red and processed meats, butter, high fat dairy products, eggs, sweets and desserts, French fries, and refined grains. Details of the reproducibility and validity of dietary patterns assessed with a food frequency questionnaire have been previously described. 30 31

The Alternative Healthy Eating Index measures adherence to a dietary pattern based on foods and nutrients most predictive of risk for chronic disease in the literature. 32 The Alternative Healthy Eating Index ranges from 0 to 110 points. Each of the 11 components of the score (vegetables, fruits, whole grains, sugar sweetened drinks, nuts and legumes, red and processed meat, trans fat, long chain (n-3) fats, polyunsaturated fatty acids, sodium, and alcohol) has a minimum score of 0 (worst) and a maximum score of 10 (best), according to component specific criteria reflecting either the current dietary guidelines or associations reported in the literature. Details of component selection and Alternative Healthy Eating Index calculation have been previously described. 32

Covariate assessment

In addition to age at blood draw, we collected information on factors potentially associated with Mediterranean diet and telomere length. Using the biennial questionnaires completed proximal to blood collection and a supplemental questionnaire administered at blood collection, we assessed various anthropometric, reproductive, and lifestyle factors, as well as factors that have been related to telomere length in the Nurses' Health Study elsewhere: body mass index (kg/m ²), cigarette smoking (pack years), 33 34 35 physical activity (total metabolic equivalent hours of activity per week). 16 We calculated dietary factors, including energy intake (total calories), from the 1990 food frequency questionnaire.

Telomere length measurement

Genomic DNA was extracted from peripheral blood leukocytes using the QIAmp 96-spin blood protocol (Qiagen, Chatsworth, CA, USA). Pico-Green quantification of genomic DNA was performed using a Molecular Devices 96 well spectrophotometer (Sunnyvale, CA, USA).

Relative telomere length was determined using a modified, high throughput version of the quantitative real time polymerase chain reaction based telomere assay. 36 37 The quantitative real time polymerase chain reaction telomere assay was run on the Applied Biosystems 7900HT Sequence Detection System (Foster City, CA, USA). Laboratory personnel were blinded to participants' characteristics, and all assays were processed in triplicate by the same technician and under identical conditions.

The average relative leukocyte telomere length was calculated as the ratio of telomere repeat copy number to a single gene (36B4) copy number. Leukocyte telomere length is reported as the exponentiated ratio of telomere repeat copy number to a single gene copy number corrected for a reference sample. In all nested case-control studies, the telomere and single gene assay coefficients of variation for triplicates were less than 4%. Coefficients of variation for the exponential ratio of telomere repeat copy number to a single gene copy number were under 18%. In the Nurses' Health Study, the three year and 10 year interclass correlations for reliability were determined to be 0.80 and 0.60. Although this assay provides a relative measurement of telomere length, ratios of telomere repeat copy number to a single gene copy number highly correlate with absolute telomere lengths determined by Southern blot ( r=0.677; P<0.001). 36

Telomere length was assayed in various batches corresponding to each study. To minimize the impact of potential batch effect on leukocyte telomere length measurements across different studies, we calculated z scores of log transformed leukocyte telomere length by standardizing the leukocyte telomere length in comparison with the mean within each individual study. 18 19 38

Statistical analysis

We used Spearman's partial rank correlation coefficients to examine age adjusted associations between characteristics of the study population, quarters of leukocyte telomere length, and Alternate Mediterranean Diet score groups.

We used multivariable linear regression models to determine the cross sectional association between leukocyte telomere length and adherence to the Mediterranean diet. We calculated multivariable adjusted least squares mean leukocyte telomere length z scores (and their corresponding 95% confidence intervals) across all dietary patterns score groups by using generalized linear models. Firstly, only age at blood draw was included in the models. Models were then additionally adjusted for other potential confounders (body mass index, smoking, physical activity, energy intake, and batch). Finally, other variables were included as potential covariates (for example, postmenopausal hormone therapy, history of hypertension, and socioeconomic status), but these were removed from the final models as estimates remained the same. All P values are two sided, and an α level of 0.05 was used. We used SAS version 9.2 for all statistical analyses. Reported STROBE guidelines have been the basis for reporting our results. 39

Comparison with previous literature

To our knowledge, this is the largest population based study specifically looking at the association between adherence to the Mediterranean diet and telomere length in healthy, middle aged women. Our results are consistent with previously published literature on the benefits of a healthy lifestyle, particularly diet, and telomere length.

To date, only one study has assessed the association between telomere length, telomerase activity, and different adherence to a Mediterranean diet. 40 The 217 older people in this study had a mean age of 77, and the upper age limit for reliable assessment of telomere length is 75. 41 Using an older age group is considered inappropriate because of "survivor" bias 42 43: people who live longer tend to be more resilient to chronic disease and possess longer telomeres. The authors may be capturing survivor bias rather than an association between telomere length and adherence to a Mediterranean diet.

García-Calzón et al studied the association between telomere length and changes in adiposity indices after a five year intervention study with a Mediterranean diet, 44 in the context of the PREDIMED-NAVARRA trial. 5 In this particular study, the outcome was obesity, and the association between telomere length and the whole Mediterranean diet was not specifically examined.

Only two studies have examined the relation between a healthy lifestyle pattern and leukocyte telomere length. 19 34 Mirabello et al observed a positive association between a healthy lifestyle (defined by low risk factors including low or no smoking, higher intakes of fruits and vegetables, lower body mass index, and greater physical activity) and leukocyte telomere length in men. 34 Similarly, Sun et al reported that a healthy lifestyle pattern (defined by five components: smoking, physical activity, adiposity, alcohol use, and Alternative Healthy Eating Index) was associated with longer leukocyte telomere length in women. 19

One of the first studies to show a strong relation between physical fitness and telomere length in a large sample of patients with existing coronary heart disease was conducted by Krauss et al. 45 They found that poor physical fitness was associated with shorter leukocyte telomere length in patients with coronary heart disease. Du et al reported, in the Nurses' Health Study, that physical activity (even moderate amounts of activity) was associated with longer telomeres. 16 Moreover, Ornish et al recently published an intervention trial on the effect of comprehensive lifestyle changes (diet, activity, stress management, and social support) on telomerase activity and telomere length in men with low risk prostate cancer. 46 Results from this pilot study showed that a comprehensive lifestyle intervention was associated with increases in relative telomere length after five years of follow-up, compared with controls.

Studies on the association between specific dietary factors and telomere length have yielded inconsistent results. 34 47 48 49 50 Cassidy et al, for instance, reported a positive association between leukocyte telomere length and dietary fiber intake but an inverse association between total fat intake (particularly, polyunsaturated fatty acids) and leukocyte telomere length. No significant associations were observed for intakes of vitamin D or fruits and vegetables. 50 These findings support the importance of examining an overall lifestyle dietary pattern, rather than individual food components.

The Mediterranean diet score has been used to evaluate the association between the Mediterranean diet and overall mortality, as well as Alzheimer's disease, diabetes mellitus, coronary heart disease, and cancer overall. 2 51 52 53 54 55 Trichopoulou A et al evaluated the contribution of the nine widely accepted components, which are used to build the Mediterranean diet score, and reported an inverse association of this diet with all cause mortality in a population based cohort in Greece. 56 More interestingly, they found additive associations among components. The authors report that one of the advantages of using a Mediterranean diet score rather than focusing on the food components is the generation of fairly consistent results with respect to health benefits, whereas studies focusing on the components or food groups are often contradictory. As summarized by Trichopoulou et al, 56 chance, non-differential misclassification, and residual confounding may have more important consequences when individual food items are evaluated rather than a multi-component, unidimensional score.

The benefits on health and aging from a greater adherence to the Mediterranean diet have been largely described. Adherence to the Mediterranean diet has been linked to lower all cause mortality, reduced incidence of major cardiovascular diseases and other chronic diseases, and greater health and wellbeing in people surviving to older ages. 2 3 4 5 6

Possible biologic mechanisms

Oxidative stress and inflammation have been reported to accelerate telomere attrition. 10 11 57 Moreover, given human telomere composition, these DNA regions are more sensitive to damage by oxidation. 58 59 In contrast, high antioxidative capacity slows telomere shortening. 58 60 61 62 The established protective effects of the Mediterranean diet on oxidative stress and chronic inflammation may explain the favorable influence of the Mediterranean diet on telomere length, pointing to a potential biologic mechanism behind the well known anti-aging effects of the Mediterranean diet.

The lack of an association with individual components is not surprising. Studies have proposed a possible synergy among the nutrient rich foods included in the Mediterranean diet that fosters favorable changes in intermediate pathways of cardiometabolic risk, such as insulin sensitivity and resistance to oxidation and inflammation, 5 63 supporting the role of the Mediterranean diet as a whole.

Strengths and limitations of study

The strengths of our study include the large and well characterized study population, detailed assessment of dietary habits as well as other sociodemographic and lifestyle characteristics, and validated food frequency questionnaires and dietary scores. However, potential limitations should be considered. The cross sectional design precludes us from establishing a temporal association between dietary habits and telomere length. Leukocyte telomere length was assessed using a single measure, preventing the estimation of associations between Mediterranean diet and telomere attrition rate; assessing this requires a prospective study with repeated assessments of leukocyte telomere length. Although all analyses were adjusted for multiple covariates, unmeasured or residual confounding could still be present. Validation of self reported variables potentially associated with telomere length, such as self reported diabetes, hypertension, and obesity, has been done previously. 64 65 66 Finally, the Nurses' Health Study population predominantly includes women of European ancestry, and telomere dynamics may differ among other ethnicities 67 68 69; therefore, results may not be generalized. However, the homogeneity among Nurses' Health Study participants strengthens the internal validity of these findings by maximizing the quality of reported data.

Conclusion

In summary, greater adherence to the Mediterranean diet was significantly associated with longer leukocyte telomere length, a marker of biological aging. Our results further support the health benefits of adherence to the Mediterranean diet.

Cite this as: BMJ 2014;349:g6674

View Abstract

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Mediterranean diet and telomere length in Nurses' Health Study: population based cohort study

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The Nurses' Health Study is a prospective cohort study of 121 700 female registered nurses in 11 US states, aged 30-55 years at enrollment. The study was established in 1976; since then, participants have completed biennial questionnaires to update information on demographic characteristics, lifestyle factors, and newly diagnosed diseases.

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A Mediterranean Diet Helps Your Cells Live Longer -- ScienceDaily

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A Mediterranean Diet Helps Your Cells Live Longer -- ScienceDaily