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Category: cardiovascular health

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Some recent studies looked at aspirin use and cancer and found that consistent use for a number of years (5 to 10 years) lowers the rate of a number of cancers, including colon cancer. However, the longer one takes daily aspirin - then harms start adding up, with a major one being gastrointestinal bleeding. NSAIDs (non-steroidal anti-inflammatory drugs) are also linked to lower rates of various cancers, but harms with long-term use are cardiovascular risks (stroke and heart attack). The first article discusses that many doctors think this lower cancer rate occurs because aspirin and NSAIDs lower inflammation, and as we know, inflammation is linked to cancer.

From Science News: Aspirin reverses obesity cancer risk

Research has shown that a regular dose of aspirin reduces the long-term risk of cancer in those who are overweight in an international study of people with a family history of the disease....They found that being overweight more than doubles the risk of bowel cancer in people with Lynch Syndrome, an inherited genetic disorder which affects genes responsible for detecting and repairing damage in the DNA. Around half of these people develop cancer, mainly in the bowel and womb. However, over the course of a ten year study they found this risk could be counteracted by taking a regular dose of aspirin.

Lots of people struggle with their weight and this suggests the extra cancer risk can be cancelled by taking an aspirin.This research adds to the growing body of evidence which links an increased inflammatory process to an increased risk of cancer. Obesity increases the inflammatory response. One explanation for our findings is that the aspirin may be suppressing that inflammation which opens up new avenues of research into the cause of cancer."

When they were followed up ten years later, 55 had developed bowel cancers and those who were obese were more than twice as likely to develop this cancer -- in fact 2.75 times as likely. Following up on patients who were taking two aspirins a day revealed that their risk was the same whether they were obese or not....What is surprising is that even in people with a genetic predisposition for cancer, obesity is also a driver of the disease. 

The researchers believe the study shows that aspirin is affecting an underlying mechanism which pre-disposes someone to cancer and further study is needed in this area. Since the benefits are occurring before the very early stages of developing a tumour -- known as the adenoma carcinoma sequence -- the effect must be changing the cells which are predisposed to become cancerous in later years.

...continue reading "Aspirin and Cancer"

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 Artificial trans fats in foods are bad for health in so many ways: linked to increased risk of coronary heart disease, atherosclerosis, inflammation, and risk of early death. And even though the FDA is finally phasing out partially hydrogenated oils (because they have high levels of artificial trans fats) within the next 3 years, trans fats will still be found in foods (processed foods). How can this be? Well, trans fats are still allowed to be in foods that are labeled as 0 trans fats if it is less than .5 grams trans fats per serving (a loophole allows them to round downward to zero ). And according to research by Environmental Working Group (EWG), trans fats are being used by the food industry in undisclosed ways in amounts low enough to exploit the trans fat loophole. Besides partially hydrogenated oils, they are found in other types of refined oils, monoglycerides, diglycerides and other emulsifiers, and even in flavors and colors. So when you see ZERO trans fats on the label, it doesn't actually mean that it is zero trans fats. The problem is that over the course of a day, eating a number of foods and servings that have under .5 grams of trans fats adds up to levels that research now says has negative health effects!

Artificial trans fats are found in a lot of processed foods. A EWG analysis found that harmful artificial trans fatty acids lurk in more than 27 percent of more than 84,000 processed foods common in American supermarkets.  Another 10 percent contain ingredients likely to contain trans fat. Foods most likely to have hidden trans fats are: breakfast bars, granola and trail mix bars, pretzels, peanut butter, crackers, breads, kids fruit snacks, kids cereal, graham crackers, whipped topping, non-dairy creamers, pudding mixes, cupcakes, and ice cream cones.

So what can you do? Read ingredient lists on labels and try to avoid foods with the above mentioned ingredients: partially hydrogenated oils, emulsifiers, monoglycerides, diglycerides and other emulsifiers, artificial flavors, artificial flavors, and colors. Try to cut back or avoid foods that have ingredients that are not real foods - tough to do, but it can be done.

And the amazing part, saturated fats (such as butter) are NOT linked to early death and heart disease, but trans fat in foods is. Latest research, from Science Daily:

Trans fats, but not saturated fats like butter, linked to greater risk of early death and heart disease

A study led by researchers at McMaster University has found that that trans fats are associated with greater risk of death and coronary heart disease, but saturated fats are not associated with an increased risk of death, heart disease, stroke, or Type 2 diabetes. The findings were published today by the British Medical Journal (BMJ)...."For years everyone has been advised to cut out fats. Trans fats have no health benefits and pose a significant risk for heart disease, but the case for saturated fat is less clear," said de Souza.

Saturated fats come mainly from animal products, such as butter, cows' milk, meat, salmon and egg yolks, and some plant products such as chocolate and palm oils. Trans unsaturated fats (trans fats) are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods.

Contrary to prevailing dietary advice, a recent evidence review found no excess cardiovascular risk associated with intake of saturated fat. In contrast, research suggests that industrial trans fats may increase the risk of coronary heart disease.

To help clarify these controversies, de Souza and colleagues analysed the results of 50 observational studies assessing the association between saturated and/or trans fats and health outcomes in adults....The team found no clear association between higher intake of saturated fats and death for any reason, coronary heart disease (CHD), cardiovascular disease (CVD), ischemic stroke or type 2 diabetes. However, consumption of industrial trans fats was associated with a 34 per cent increase in death for any reason, a 28 per cent increased risk of CHD mortality, and a 21 per cent increase in the risk of CHD.

Inconsistencies in the studies analysed meant that the researchers could not confirm an association between trans fats and type 2 diabetes. And, they found no clear association between trans fats and ischemic stroke. The researchers stress that their results are based on observational studies, so no definitive conclusions can be drawn about cause and effect.

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Trans fats are commonly used in processed foods to improve taste, texture, and shelf life. Artificial trans fats are found in partially hydrogenated oils and in other ingredients, such as refined oils, emulsifiers, flavors and colors. Even those processed foods that say zero trans fats may contain trans fats - due to a loophole in labeling laws (if it has less than .5 grams per serving, then it can be rounded down to zero - thus allowing the incorrect claim of zero trans fats). Eating a variety of processed foods, each containing a little trans fats, easily adds up to eating a significant amount daily.Trans fats in the diet have long been linked to cardiovascular disease, artherosclerosis, obesity, oxidative stress, and inflammation, but now research finds that it is linked to a poorer memory in middle-aged men under the age of 45. From Science Daily:

Dietary trans fat linked to worse memory

Higher consumption of dietary trans fatty acids (dTFA), commonly used in processed foods to improve taste, texture and durability, has been linked to worsened memory function in men 45 years old and younger, according to a study.

Researchers evaluated data from 1,018 men and women who were asked to complete a dietary survey and memory test involving word recall. On average, men aged 45 and younger recalled 86 words; however, for each additional gram of trans fats consumed daily, performance dropped by 0.76 words. This translates to an expected 12 fewer words recalled by young men with dTFA intake levels matching the highest observed in the study, compared to otherwise similar men consuming no trans fats.

After adjusting for age, exercise, education, ethnicity and mood, the link between higher dTFA and poorer memory was maintained in men 45 and younger.The study focused predominantly on men because of a small number of women in this age group. However, including women in the analysis did not change the finding, said Golomb. An association of dTFA to word memory was not observed in older populations. Golomb said this is likely due to dietary effects showing more clearly in younger adults. Insults and injuries to the brain accrue with age and add variability to memory scores that can swamp ability to detect diet effects.

Trans fatty acids have been linked to negative effects on lipid profiles, metabolic function, insulin resistance, inflammation and cardiac and general health. In 2013, the United States Food and Drug Administration issued a preliminary determination that trans fats were no longer generally recognized as safe. According to the Centers for Disease Control, reducing dTFA consumption could prevent 10,000 to 20,000 heart attacks and 3,000 to 7,000 coronary heart disease deaths per year in the U.S.

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Once again, research shows that eating lots of fruits and vegetables is beneficial to health - this time because high vitamin C concentrations in the blood is linked to lower risks of developing cardiovascular disease and early death. And it's food that they looked at, not supplements. From Science Daily:

Vitamin C related to reduced risk of cardiovascular disease, early death

New research from the University of Copenhagen and Herlev and Gentofte Hospital showshealth benefitsthat high vitamin C concentrations in the blood from the intake of fruit and vegetables are associated with a reduced risk of cardiovascular disease and early death.

As part of the study, the researchers had access to data about 100,000 Danes and their intake of fruit and vegetables as well as their DNA. "We can see that those with the highest intake of fruit and vegetables have a 15% lower risk of developing cardiovascular disease and a 20% lower risk of early death compared with those who very rarely eat fruit and vegetables. At the same time, we can see that the reduced risk is related to high vitamin C concentrations in the blood from the fruit and vegetables," says Camilla Kobylecki, a medical doctor and PhD student at the Department of Clinical Biochemistry, Herlev and Gentofte Hospital.

Among other things, vitamin C helps build connective tissue which supports and connects different types of tissues and organs in the body. Vitamin C is also a potent antioxidant which protects cells and biological molecules from the damage which causes many diseases, including cardiovascular disease. The human body is not able to produce vitamin C, which means that we must get the vitamin from our diet.

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Foods with trans fats. Credit: Wikipedia.

Finally the FDA is phasing out the use of artificial trans fats in foods (found in partially hydrogenated vegetable oils) within 3 years. It turns out that even though for many years scientists and the medical community pushed foods such as margarine (which have trans fats) as healthier than saturated fats such as butter, they were wrong. Instead the trans fats are linked to cardiovascular problems.

We can thank 100 year old Frank Kummerow for the ban, and for warning about trans fats for six decades! He is still drinking whole milk, eating eggs and butter, but he does avoid "fried foods, margarine, and anything associated with partially-hydrogenated oils". Other foods that are currently viewed as healthy by the medical community are extra virgin olive oil and coconut oil. However, please note that canola oil, currently viewed as a healthy and safe alternative to partially hydrogenated oils, also contains trans fats (due to the manufacturing process) and should be avoided. Also keep in mind that companies are allowed to say they have zero trans fat of they contain less than 0.5 grams per serving (which means the trans fats can add up over the course of a day). From The Washington Post:

The 100-year-old scientist who pushed the FDA to ban artificial trans fat

No one was more pleased by the Food and Drug Administration's decision Tuesday to eliminate artificial trans fats from the U.S. food supply than Fred Kummerow, a 100-year-old University of Illinois professor who has warned about the dangers of the artery-clogging substance for nearly six decades."Science won out," Kummerow, who sued the FDA in 2013 for not acting sooner, said in an interview from his home in Illinois. "It's very important that we don't have this in our diet."

In the 1950s, as a young university researcher, Kummerow convinced a local hospital to let him examine the arteries of people who had died from heart disease. He made a jarring discovery. The tissue contained high levels of artificial trans fat, a substance that had been discovered decades earlier but had become ubiquitous in processed foods throughout the country.

Later, he conducted a study showing that rats developed atherosclerosis after being fed artificial trans fats. When he removed the substance from their diets, the atherosclerosis disappeared from their arteries.

Kummerow first published his research warning about the dangers of artery-clogging trans fats in 1957. More than a decade later, while serving on a subcommittee of the American Heart Association, he detailed the massive amounts of trans fat in the shortening and margarines lining grocery shelves, and helped convince the food industry to lower the content in certain products.

Despite Kummerow's research and warnings over the years, artificial trans fats remained a staple of processed food for decades. Well into the 1980s, many scientists and public health advocates believed that partially hydrogenated oils were preferable to more natural saturated fats. And the food industry was reluctant to do away with artificial trans fats, which were cheaper than their natural counterparts, extended shelf life and gave foods desirable taste and texture.

Frustrated by the lack of action, Kummerow filed a 3,000-word citizen petition with the FDA in 2009, citing the mounting body of evidence against trans fat. The first line read: "I request to ban partially hydrogenated fat from the American diet."

In the 1990s, more and more studies had shown that trans fats were a key culprit in the rising rates of heart disease. The advocacy group Center for Science in the Public Interest also petitioned the FDA in 1994 to require that the substance be listed on nutrition labels -- a move that the agency put into place in 2006. In 2002, the Institute of Medicine found that there was “no safe level of trans fatty acids and people should eat as little of them as possible.” As the dangers of trans fat became clearer, public opinion also shifted, and food companies increasingly removed the substance from products, though it remained in a broad range of foods, from cake frostings to baked goods.

Four years after filing his petition and hearing nothing, Kummerow sued the FDA and the Department of Health and Human Services in 2013, with the help of a California law firm. The suit asked a judge to compel the agency to respond to Kummerow's petition and "to ban partially hydrogenated oils unless a complete administrative review finds new evidence for their safety."

Three months later, the FDA announced its plans to effectively eliminate trans fats by saying that the substance no longer would be assumed safe for use in human foods. Tuesday's action finalizes that initial proposal, and manufacturers will have three years to reformulate products or to petition the agency for an exception.

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New research finding health benefits to humans from a four day low calorie diet - the Fasting Mimic Diet (FMD). Cutting calories to 34 to 54% of normal for a few days is obviously much easier to do than actual fastiing, so these results look very promising. In summary: the researchers found that in a small human trial, three cycles of this diet given to 19 subjects once a month for five days decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease and cancer (and with no major adverse side effects). Three earlier posts on various types of minifasting health benefits: Minifasting May Benefit Health, Health Benefits of Feast and Famine Diet, Fasting and the Immune System. From Science Daily:

Diet that mimics fasting appears to slow aging

Want to lose abdominal fat, get smarter and live longer? New research led by USC's Valter Longo shows that periodically adopting a diet that mimics the effects of fasting may yield a wide range of health benefits. In a new study, Longo and his colleagues show that cycles of a four-day low-calorie diet that mimics fasting (FMD cut visceral belly fat and elevated the number of progenitor and stem cells in several organs of old mice -- including the brain, where it boosted neural regeneration and improved learning and memory.

The mouse tests were part of a three-tiered study on periodic fasting's effects -- testing yeast, mice and humans...Mice, which have relatively short life spans, provided details about fasting's lifelong effects. Yeast, which are simpler organisms, allowed Longo to uncover the biological mechanisms that fasting triggers at a cellular level. And a pilot study in humans found evidence that the mouse and yeast studies were applicable to humans.

In a pilot human trial, three cycles of a similar diet given to 19 subjects once a month for five days decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease and cancer with no major adverse side effects, according to Longo.

The diet slashed the individual's caloric intake down to 34 to 54 percent of normal, with a specific composition of proteins, carbohydrates, fats and micronutrients. It decreased amounts of the hormone IGF-I, which is required during development to grow, but it is a promoter of aging and has been linked to cancer susceptibility. It also increased the amount of the hormone IGFBP-, and reduced biomarkers/risk factors linked to diabetes and cardiovascular disease, including glucose, trunk fat and C-reactive protein without negatively affecting muscle and bone mass.

Longo has previously shown how fasting can help starve out cancer cells while protecting immune and other cells from chemotherapy toxicity. 'It's about reprogramming the body so it enters a slower aging mode, but also rejuvenating it through stem cell-based regeneration,' Longo said. 'It's not a typical diet because it isn't something you need to stay on.'

For 25 days a month, study participants went back to their regular eating habits -- good or bad -- once they finished the treatment. They were not asked to change their diet and still saw positive changes. Longo believes that for most normal people, the FMD can be done every three to six months, depending on the abdominal circumference and health status. For obese subjects or those with elevated disease risk factors, the FMD could be recommended by the physician as often as once every two weeks. His group is testing its effect in a randomized clinical trial, which will be completed soon, with more than 70 subjects.

Despite its positive effects, Longo cautioned against water-only fasting and warned even about attempting the fasting mimicking diet without first consulting a doctor and seeking their supervision throughout the process....Longo also cautioned that diabetic subjects should not undergo either fasting or fasting mimicking diets while receiving insulin, metformin or similar drugs. He also said that subjects with body mass index less than 18 should not undergo the FMD diet.

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Image result for dark chocolate My kind of study! Eating up to 100 grams of chocolate every day is linked to lowered heart disease and stroke risk. Not just dark chocolate, but milk chocolate also. Note that 100 grams of chocolate is equal to about 3.5 ounces chocolate.From Science Daily:

Chocolate for your heart

Eating up to 100 g of chocolate every day is linked to lowered heart disease and stroke risk. The calculations showed that compared with those who ate no chocolate higher intake was linked to an 11% lower risk of cardiovascular disease and a 25% lower risk of associated death.

They base their findings on almost 21,000 adults taking part in the EPIC-Norfolk study, which is tracking the impact of diet on the long term health of 25,000 men and women in Norfolk, England, using food frequency and lifestyle questionnaires.... were monitored for an average of almost 12 years, during which time 3013 (14%) people experienced either an episode of fatal or non-fatal coronary heart disease or stroke. Around one in five (20%) participants said they did not eat any chocolate, but among the others, daily consumption averaged 7 g, with some eating up to 100 g.

Higher levels of consumption were associated with younger age and lower weight (BMI), waist: hip ratio, systolic blood pressure, inflammatory proteins, diabetes and more regular physical activity --all of which add up to a favourable cardiovascular disease risk profile.Eating more chocolate was also associated with higher energy intake and a diet containing more fat and carbs and less protein and alcohol.

And among the 16,000 people whose inflammatory protein (CRP) level had been measured, those eating the most chocolate seemed to have an 18% lower risk than those who ate the least.The highest chocolate intake was similarly associated with a 23% lower risk of stroke, even after taking account of other potential risk factors.

Of nine relevant studies included in the systematic review, five studies each assessed coronary heart disease and stroke outcome, and they found a significantly lower risk of both conditions associated with regular chocolate consumption. And it was linked to a 25% lower risk of any episode of cardiovascular disease and a 45% lower risk of associated death.

This is an observational study so no definitive conclusions about cause and effect can be drawn. ...Nevertheless, they add: "Cumulative evidence suggests that higher chocolate intake is associated with a lower risk of future cardiovascular events."And they point out that as milk chocolate, which is considered to be less 'healthy' than dark chocolate, was more frequently eaten by the EPIC-Norfolk participants, the beneficial health effects may extend to this type of chocolate too. 

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This latest study confirms the benefits of eating peanuts and nuts. The Netherlands Cohort Study has studied 120, 000 Dutch men and women since 1986, and they found that eating approximately 1/2 handful of peanut or nuts per day is linked to a lower risk of mortality. However, this beneficial effect did not apply to peanut butter, and they theorize that it may be due to the added ingredients in it (salt and vegetable oils that are trans fats) that negate the beneficial effects of nuts. And perhaps eating an all natural peanut butter would have the same beneficial effects as plain nuts.

Note: Since 2013 even the United States FDA has said that partially hydrogenated oils (they are artificially made through an industrial process and contain trans fats) are no longer "generally recognized as safe" because they are linked to heart disease. So in general avoid all products with "partially hydrogenated" in the ingredients. From Science Daily:

Nuts and peanuts -- but not peanut butter -- linked to lower mortality rates, study finds

A paper published in the International Journal of Epidemiology confirms a link between peanut and nut intake and lower mortality rates, but finds no protective effect for peanut butter. Men and women who eat at least 10 grams of nuts or peanuts per day have a lower risk of dying from several major causes of death than people who don't consume nuts or peanuts.

The reduction in mortality was strongest for respiratory disease, neurodegenerative disease, and diabetes, followed by cancer and cardiovascular diseases. The effects are equal in men and women. Peanuts show at least as strong reductions in mortality as tree nuts, but peanut butter is not associated with lower mortality, researchers from Maastricht University found. This study was carried out within the Netherlands Cohort Study, which has been running since 1986 among over 120,000 Dutch 55-69 year old men and women. 

The associations between nuts and peanut intake and cardiovascular death confirm earlier results from American and Asian studies that were often focused on cardiovascular diseases. However, in this new study, it was found that mortality due to cancer, diabetes, respiratory, and neurodegenerative diseases was also lowered among users of peanuts and nuts. Project leader and epidemiologist Professor Piet van den Brandt commented: "It was remarkable that substantially lower mortality was already observed at consumption levels of 15 grams of nuts or peanuts on average per day (half a handful). A higher intake was not associated with further reduction in mortality risk. This was also supported by a meta-analysis of previously published studies together with the Netherlands Cohort Study, in which cancer and respiratory mortality showed this same dose-response pattern."

Peanuts and tree nuts both contain various compounds such as monounsaturated and polyunsaturated fatty acids, various vitamins, fiber, antioxidants, and other bioactive compounds, that possibly contribute to the lower death rates. In contrast to peanuts, no association was found between peanut butter intake and mortality risk. However, besides peanuts, peanut butter contains also added components like salt and vegetable oils. In the past, it has been shown that peanut butter contains trans fatty acids and therefore the composition of peanut butter is different from peanuts. The adverse health effects of salt and trans fatty acids could inhibit the protective effects of peanuts.

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A wonderful commentary by Dr. Mandrola about recent research of almost 500,000 UK citizens. Researchers found that just asking the patient several basic questions was a better predictor of 5 year mortality than all sorts of blood tests, measurements, and analyses. The best basic questions were: Is your health excellent, good, average, or poor? Is your walking pace slow, average, or brisk? Along with smoking, those two basic questions were the best predictors of staying alive in the next 5 years. These excerpts are from Medscape:

Health Is Not Complicated—Just Ask the Patient

It turns out predicting health is not so complicated. Nor is it digital at all. For persons of middle age (40 to 70 years), self-reported overall health and walking speed were the best predictors of death in the next 5 years, according to a study published this week in the Lancet.[1]

In an analysis of nearly 500,000 UK citizens followed for 5 years, these two simple questions outperformed 655 measurements of demographics, health, and lifestyle. Is your health excellent, good, average, or poor? Is your walking pace slow, average, or brisk? Along with smoking, those two basic questions, inquiries that hardly require a digital device, were the best predictors of staying alive in the next 5 years.

Pause for a moment here and ponder the beauty of that top-line result. Half a million people followed for 5 years; 655 measures of health, including heart rate, blood pressure, and lab tests, and the best predictors were that simple.

In the 5 years of follow-up, 8532 (1.7%) subjects died. Overall, cancer was the most common cause of death (53% in men; 69% in women). The most common cancer-related cause of death was lung cancer in men (n=546) and breast cancer in women (n=489). Cardiovascular disease was the second leading cause of death (26% in men; 33% in women).

 

There were gender differences in predictors of death. Self-reported health was the strongest predictor of death in men (C index 0.74). In women, a previous cancer diagnosis was the strongest predictor (C index 0.73).Self-reported walking pace was a strong predictor of death in both men and women (C index 0.72 and 0.69, respectively.) For example, a man aged 40 to 52 years who reported a slow walking pace was 3.7 times more likely to die than a similarly aged man who reported a steady walking pace. In a large subset of subjects with no reported health conditions, smoking was the best predictor of mortality.

 

The final, and perhaps niftiest, aspect of this study was that researchers developed an 11 to 13 question risk prediction score, which they then put on an interactive website. Anyone can answer these simple questions and get their health-related age relative to the UK population. The researchers call this age the UK Longevity Explorer (UbbLE) age.

I am drawn to these findings because they emphasize something that is increasingly lost on both doctors and patients. True health is not complicated. And the big picture is still useful.Any experienced clinician will testify that patients know when they are well and when they are not. The finding that self-reported health predicts death urges clinicians, generalists and specialists alike, to ask our patients how they feel about their health.

Then there is the matter of self-reported walking pace. How easy it is to be distracted by digital data. We walk into the exam room to see our patient. He is still. We look at him. We poke and listen to his body. We assess his ECG and other measures. Soon we will review his smartphone metrics and DNA data. Yet we tend to forget the obvious: to move is to be healthy. Drs Ganna and Ingelsson teach us that to move briskly may be healthier.

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Image result for Mediterranean dietMore support for health benefits of a Mediterranean diet. Results of a  study comparing brain health in groups of older people (in their 60s and 70s) suggest that a Mediterranean diet supplemented with olive oil or nuts may counter-act age-related cognitive decline (overall their cognitive test scores held steady). But the group assigned to the low-fat diet (the control group) worsened on cognitive tests. The Mediterranean diet emphasizes eating vegetables, fruits, legumes (beans), nuts, whole grains, seeds, olive oil, fish, moderate consumption of dairy products (mostly as cheese and yogurt), moderate wine consumption (optional), and low consumption of meat and meat products.From the Wall Street Journal:

Mediterranean Diet Boosts Brain Power, Clinical Study Finds

The Mediterranean diet, supplemented with a handful of nuts or a few tablespoons of olive oil a day, can counteract the effects of aging on the brain’s ability to function, a new clinical study suggests.

The study, published online Monday in JAMA Internal Medicine, was unusual in that it employed rigorous scientific practices to test the effect of the diet on health....Data gathered from previous observational studies suggested that adhering to a Mediterranean-type diet related to better cognitive function and a reduced risk of dementia, but observational studies have limitations, he said.

The Mediterranean diet, which has also shown benefits in cardiovascular health, emphasizes vegetables and fruits, unrefined grains and beans. It also includes fish and wine and minimal consumption of meat and full-fat dairy products.

The study involved 447 cognitively healthy participants, 55 to 80 years of age, who were divided into three groups. Two groups followed the Mediterranean diet and added either 30 grams of mixed nuts (walnuts, hazelnuts and almonds) a day, or five tablespoons of extra virgin olive oil a day. The third group, acting as a control, was advised to follow a low-fat diet. The subjects were followed for a median of just over four years.

The results showed that, compared with the control group, memory function remained stronger in the Mediterranean diet plus nuts group, while frontal (attention and executive function) and global cognition benefited in the Mediterranean diet plus olive oil group.

The diminished decline in cognitive function likely stems from the abundance of antioxidants and anti-inflammatory agents found in the supplemental foods, Dr. Ros said. Olive oil and nuts are rich in phenolic compounds that might counteract oxidative processes in the brain, leading to neurodegeneration, the study said. “If you can delay your age-related cognitive decline, you can process tasks with higher speed,” said Dr. Ros.

The research was a substudy of a larger investigation, designed by Dr. Ros, that found the Mediterranean diet, supplemented with additional olive oil or nuts, reduced the incidence of major cardiovascular events among people at high cardiovascular risk. That study, which involved nearly 7,500 participants and known by the acronym Predimed, was published in 2013.