Mediterranean diet high in healthy fat does not lead to weight gain,

Focus on low-fat diets and lack of differentiation between healthy and unhealthy fat has led to 'paradoxical policies' about healthy eating

Eating a non-calorie restricted Mediterranean diet high in vegetable fats such as olive oil or nuts does not lead to significant weight gain compared to a low-fat diet, according to a large randomised trial published today in The Lancet Diabetes & Endocrinology journal. The study suggests that current health guidelines that recommend a low-fat, low-calorie diet create unnecessary fear of healthy fats present in a Mediterranean diet, which have known health benefits.

Accumulating scientific evidence suggests that total fat content is not a useful measure of harms or benefits of food, and that fats from nuts, fish and phenolic-rich vegetable oils are healthier than fats from meat and processed foods.

"More than 40 years of nutritional policy has advocated for a low-fat diet but we're seeing little impact on rising levels of obesity," says lead author Dr Ramon Estruch, CIBER OBN-University of Barcelona, Spain. "Our study shows that a Mediterranean diet rich in vegetable fats such as olive oil and nuts had little effect on bodyweight or waist circumference compared to people on a low-fat diet. The Mediterranean diet has well-known health benefits and includes healthy fats such as vegetable oils, fish and nuts. Our findings certainly do not imply that unrestricted diets with high levels of unhealthy fats such as butter, processed meat, sweetened beverages, deserts or fast-foods are beneficial." [1]

Obesity is a key risk factor for cardiovascular disease, type 2 diabetes, some cancers and musculoskeletal disorders. The standard recommendation for the prevention and treatment of obesity is a reduced-fat diet and increased physical activity, and many health organisations including WHO recommend a limit of 30% fat for total energy intake [2].

Perceptions of all fat as unhealthy have resulted in decreased fat consumption in the US population, but the epidemics of obesity and diabetes have continued to grow. Numerous studies have shown that the Mediterranean diet, which includes high levels of vegetable fats (e.g. olive oil, nuts), is linked to reduced mortality, cardiovascular disease and cancer, but fears of eating all fat mean that a low-fat diet continues to be recommended as a means of weight loss.

The study took place in 11 hospitals in Spain during 2003-2010 and included 7447 participants (men and women) aged 55-80 who were randomly assigned to one of three groups - an unrestricted-calorie Mediterranean diet rich in olive oil (2543), an unrestricted-calorie Mediterranean diet rich in nuts (2454), or a low-fat diet where the advice was to avoid all dietary fat (2450) [3]. Trained dieticians gave personalised dietary advice to all participants.

Adherence to the diets was good and monitored by questionnaires for all participants and by taking blood and urine samples in a random subgroup. All participants were at high cardiovascular risk [4] or had type 2 diabetes, and more than 90% were overweight or obese.

After 5 years, total fat intake had decreased in the low-fat diet group (from 40% to 37.4%) and had slightly increased in both Mediterranean diet groups (40% to 41.8% in olive oil; 40.4% to 42.2% in nuts). The percentage of energy intake from protein and carbohydrate decreased in both Mediterranean diet groups.

On average, participants in all three groups lost some weight with the greatest weight loss seen in the Mediterranean diet with olive oil group (0.88 kg weight reduction in the olive oil group, compared to 0.60 kg for the low-fat diet group and 0.40 kg for the nuts group - figure 2). There was an increase in waist circumference in all three groups with the greatest increase seen in the low-fat diet group (1.2 cm increase for the low-fat diet group, compared to 0.85 cm for the olive oil group and 0.37 cm for the nuts group - figure 3).

Writing in a linked Comment, Professor Dariush Mozaffarian, Friedman School of Nutrition Science & Policy at Tufts University, Boston, MA, USA says: "Ironically, just as focusing on total fat to prevent heart disease was misguided because it overlooked the different effects of specific fatty acids, the prioritisation of total calories (and by extension, total fat) to prevent weight gain ignores the diverse physiological effects of different foods. Although the rationale has morphed over time, the end result is similar: a proliferation of fat-reduced--and often correspondingly starch-rich and sugar-rich--foods and diets, with paradoxical warnings and caveats about eating healthy, high-fat foods, such as those rich in nuts and vegetable oils."

"Dietary guidelines should be revised to lay to rest the outdated, arbitrary limits on total fat consumption. Calorie-obsessed caveats and warnings about healthier, higher-fat choices such as nuts, phenolic-rich vegetable oils, yoghurt, and even perhaps cheese, should also be dropped. We must abandon the myth that lower-fat, lower-calorie products lead to less weight gain. This illusion leads to paradoxical policies that focus on total calories, rather than food quality, on restaurant menus; ban whole milk but allow sugar-sweetened fat-free milk; compel food manufacturers, retailers, and restaurants to remove healthy vegetable-derived fats from meals and products while heavily marketing fat-reduced products of dubious health value; and mislead consumers to select foods based on total fat and calorie contents rather than actual health effects."

"The fat content of foods and diets is simply not a useful metric to judge long-term harms or benefits. Energy density and total caloric contents can be similarly misleading. Rather, modern scientific evidence supports an emphasis on eating more calories from fruits, nuts, vegetables, beans, fish, yoghurt, phenolic-rich vegetable oils, and minimally processed whole grains; and fewer calories from highly processed foods rich in starch, sugar, salt, or trans-fat. We ignore this evidence-- including these results from the PREDIMED trial--at our own peril."

Beer Drinking May Be Protective against Alzheimer's

While most people will agree that excessive consumption of alcohol can have a detrimental effect on the brain, there is less agreement regarding the effects of light or moderate drinking. This includes concern and controversy surrounding the effects of drinking on the development of neurodegenerative diseases such as Alzheimer's (AD). This study investigated the association between consumption of different alcoholic beverages -- beer, wine, and spirits -- and one of the neuropathological signs of Alzheimer's disease, β-amyloid (Aβ) aggregation in the brain.

Researchers examined data from 125 males participating in the Helsinki sudden death autopsy series, who at the time of death were 35 to 70 years old. Consumption of alcohol, Aβ aggregation in the brain, and apolipoprotein E (APOE) genotype were assessed. Surviving relatives answered a questionnaire used to gather the drinking history of the deceased, and Aβ was observed by immunohistochemical staining of brain sections.

Findings suggest that beer consumption may protect against Aβ aggregation in the brain. The amount of alcohol consumed was not linked with Aβ aggregation, and neither was spirit or wine consumption. Given that the development of dementia occurs over several years and even decades, the authors call for additional studies to identify early and mid-life factors that may stimulate or protect against Aβ aggregation.

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Journal Reference: Eloise H. Kok, Toni T. Karppinen, Teemu Luoto, Irina Alafuzoff, Pekka J. Karhunen. Beer Drinking Associates with Lower Burden of Amyloid Beta Aggregation in the Brain: Helsinki Sudden Death Series. Alcoholism: Clinical and Experimental Research,

Dietary fiber intake tied to successful aging

Most people know that a diet high in fiber helps to keep us "regular." Now Australian researchers have uncovered a surprising benefit of this often-undervalued dietary component.

A new paper -- published in The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences by scientists from The Westmead Institute for Medical Research -- reports that eating the right amount of fiber from breads, cereals, and fruits can help us avoid disease and disability into old age.

Using data compiled from the Blue Mountains Eye Study, a benchmark population-based study that examined a cohort of more than 1,600 adults aged 50 years and older for long-term sensory loss risk factors and systemic diseases, the researchers explored the relationship between carbohydrate nutrition and healthy aging.

They found that out of all the factors they examined -- which included a person's total carbohydrate intake, total fiber intake, glycemic index, glycemic load, and sugar intake -- it was the fiber that made the biggest difference to what the researchers termed "successful aging."

Successful aging was defined as including an absence of disability, depressive symptoms, cognitive impairment, respiratory symptoms, and chronic diseases including cancer, coronary artery disease, and stroke.

According to lead author of the paper, Associate Professor Bamini Gopinath, PhD, from the Institute's Centre for Vision Research, the study is the first to look at the relationship between carbohydrate intake and healthy aging, and the results were significant enough to warrant further investigation.

"Out of all the variables that we looked at, fiber intake -- which is a type of carbohydrate that the body can't digest -- had the strongest influence," she said. "Essentially, we found that those who had the highest intake of fiber or total fiber actually had an almost 80 percent greater likelihood of living a long and healthy life over a 10-year follow-up. That is, they were less likely to suffer from hypertension, diabetes, dementia, depression, and functional disability."

While it might have been expected that the level of sugar intake would make the biggest impact on successful aging, Gopinath pointed out that the particular group they examined were older adults whose intake of carbonated and sugary drinks was quite low.

Although it is too early to use the study results as a basis for dietary advice, Gopinath said the research has opened up a new avenue for exploration.

"There are a lot of other large cohort studies that could pursue this further and see if they can find similar associations. And it would also be interesting to tease out the mechanisms that are actually linking these variables," she said.

This study backs up similar recent findings by the researchers, which highlight the importance of the overall diet and healthy aging.

In another study published last year in The Journals of Gerontology, Westmead Institute researchers found that, in general, adults who closely adhered to recommended national dietary guidelines reached old age with an absence of chronic diseases and disability, and had good functional and mental health status.

Long-term of marijuana: no differences in metabolism, lung function, inflammation

A long-term study of nearly 1,000 New Zealanders from birth to age 38 has found that people who smoked marijuana for up to 20 years have more gum disease, but otherwise do not show worse physical health than non-smokers.

The international research team assessed a dozen measures of physical health, including lung function, systemic inflammation and several measures of metabolic syndrome, including waist circumference, HDL cholesterol, triglycerides, blood pressure, glucose control and body mass index.
Tobacco users in the study, which appears online the week of June 1 in JAMA Psychiatry, were found to have gum disease as well as reduced lung function, systemic inflammation and indicators of poorer metabolic health.

“We can see the physical health effects of tobacco smoking in this study, but we don’t see similar effects for cannabis smoking,” said Madeline Meier, an assistant professor of psychology at Arizona State University who conducted the study with colleagues at Duke University, King’s College in the UK and the University of Otago in New Zealand.

While study participants who had used marijuana to some degree over the last 20 years showed an increase in periodontal disease from age 26 to 38, they did not differ from non-users on any of the other physical health measures. To measure cannabis use, they asked study subjects to self-report their use at ages 18, 21, 26, 32 and 38.

The study’s statistical analysis found that the decline in periodontal health in pot smokers was not explained by tobacco smoking, alcohol abuse or less tooth brushing and flossing. The lack of physical health problems among cannabis users also was not attributable to their having had better health to begin with or to living healthier lifestyles.

“We don’t want people to think, ‘Hey, marijuana can’t hurt me,’ because other studies on this same sample of New Zealanders have shown that marijuana use is associated with increased risk of psychotic illness, IQ decline and downward socioeconomic mobility,” Meier said.

“What we’re seeing is that cannabis may be harmful in some respects, but possibly not in every way,” said study co-author Avshalom Caspi, the Edward M. Arnett Professor of psychology and neuroscience at Duke. “We need to recognize that heavy recreational cannabis use does have some adverse consequences, but overall damage to physical health is not apparent in this study.”

“Physicians should certainly explain to their patients that long-term marijuana use can put them at risk for losing some teeth,” said Terrie Moffitt, the Nannerl O. Keohane University Professor of psychology and neuroscience at Duke and co-director of the Dunedin Multidisciplinary Health and Development Study, from which these data were gathered.

Women with migraines have higher risk of cardiovascular disease and mortality

Women diagnosed with migraines have a slightly increased risk of developing cardiovascular diseases, such as heart attacks and strokes, and are somewhat more likely to die from these conditions than women who do not have migraine, according to findings of a large study published in The BMJ today.

These results add to evidence that migraine should be considered an important risk marker for cardiovascular disease, say experts. But more research is needed to determine possible causes, and whether treatments to prevent migraines could help to reduce these associated risks.

Migraine has been consistently linked with an increased risk of stroke, but few studies have shown an association of migraine with cardiovascular diseases and mortality.

So a team of US and German researchers carried out a large prospective study to evaluate associations between migraine, cardiovascular disease and mortality.

They analysed data from 115,541 women enrolled in the Nurses' Health Study II. The participants were aged 25-42 years, free from angina and cardiovascular disease, and followed from 1989-2011 for cardiovascular events, diseases and mortality.

Overall, 17,531 (15.2%) women reported a physician's diagnosis of migraine at baseline. Over 20 years of follow-up, 1,329 total cardiovascular disease events occurred and 223 women died due to cardiovascular disease.

When compared to women who did not have migraine, these results show that women who reported a migraine had a greater risk for major cardiovascular disease, including heart attacks, strokes and angina/coronary revascularization procedures.

These associations remained after adjusting for other factors that may have increased the risk for these diseases.

In addition, migraine was associated with a higher risk for cardiovascular mortality. This association was similar across subgroups of women, including by age, smoking status, hypertension, postmenopausal hormone therapy, and oral contraceptive use.

In a linked editorial, Rebecca Burch from Harvard Medical School and Melissa Rayhill from The State University of New York at Buffalo caution that "the magnitude of the risk should not be over-emphasized," as "it is small at the level of the individual patient, but still important at a population level because migraine is so prevalent."

While the current study controlled for a large number of vascular risk factors, no information was available for vascular biomarkers, and migraine specifics, such as migraine aura.

Nevertheless, the authors say "these results further add to the evidence that migraine should be considered an important risk marker for cardiovascular disease, at least in women," and there is no reason why the findings can't be applicable to men.

"Given the high prevalence of migraine in the general population, an urgent need exists to understand the biological processes involved and to provide preventive solutions for patients," they conclude.

The editorialists Rebecca Burch and Melissa Rayhill agree "it's time to add migraine to the list of early life medical conditions that are markers for later life cardiovascular risk."

They say this latest study raises questions about whether treatments that decrease the frequency or severity of migraine may reduce later life vascular risks, and conclude by saying "what little evidence we do have suggests the need for therapeutic restraint [to prevent cardiovascular risk] until we have a better understanding of the mechanisms underlying the link between migraine and vascular disease."

Why are blacks at higher risk for cognitive impairment?

Social and economic disadvantages play a significant role in why blacks face a much higher risk than whites of developing cognitive impairment later in life, indicates a national study led by a Michigan State University sociologist.

The odds that blacks will develop cognitive impairment, including dementia, in later life were 2.52 times greater than the odds for whites. Much of that racial disparity was explained by childhood disadvantages, such as growing up poor and in the segregated South, and lower socioeconomic status in adulthood, particularly educational attainment.

Surprisingly, racial differences in health problems, such as heart disease and diabetes, and health behaviors, such as smoking and drinking, did not explain much of the racial gap in cognitive impairment, said Zhenmei Zhang, MSU associate professor of sociology.

While the findings do not fully explain blacks' higher risk of cognitive impairment, they point to a strong need for policymakers to focus more on reducing racial gaps in socioeconomic resources over the lifespan, she said. The federally funded study is published in the Journal of Health and Social Behavior.

"Social policies such as increasing educational resources in low-income communities, providing economic support to poor students and their families, improving graduation rates in high schools and colleges, and eliminating discrimination against blacks in the job market may significantly reduce racial disparities in cognitive impairment in later life," Zhang said.

Zhang and colleagues analyzed survey data from 8,946 participants in the Health and Retirement Study. The information was collected in multiple waves over a 12-year period (1998-2010); participants were aged 65 or older at the start of the study.

Once the researchers took into account the various socioeconomic factors, which include childhood disadvantages, the odds ratio of cognitive impairment between blacks and whites - or the racial gap - was reduced considerably, from 2.52 to 1.45. That means socioeconomic factors explained a significant amount of the racial gap.

Cognitive impairment among the elderly is a growing problem - spending on dementia care alone exceeds $100 billion a year in the United States - but it hits blacks particularly hard, Zhang noted. The Alzheimer's Association has identified Alzheimer's disease among blacks as an emerging public health crisis.

"As people live longer and longer, it becomes an even bigger issue," Zhang said.

No evidence of heart damage from long-term endurance training by elite master athletes

In 2012, Belgium scientists published a study that concluded that repeated bouts of intensive endurance exercise at the elite level may result in the pathological enlargement of the right ventricle, which, according to the article, is associated with potential health hazards including sudden cardia death. The publication was the cause of considerable debate among experts in the medical and sports communities. Sports medicine physicians at Saarland University have now tested the conclusions of the 2012 study by examining the hearts of elite master endurance athletes. Their findings refute the hypothesis proposed by their Belgian colleagues. The Saarland research team could find no evidence that years of elite-level endurance training causes any long-term damage to the right ventricle. The study has been published in the respected medical journal 'Circulation'.

The media reports with depressing regularity the sudden cardiac death of endurance athletes. Just a few weeks ago, television channels, newspapers and the internet reported that Dutch professional cyclist Gijs Verdick had died in hospital a week after suffering a double heart attack during a race.

The potential hazards that endurance exercise poses to the heart have been the subject of discussion in the medical community for over a century. Although there is now general consensus that the enlarged heart of an athlete is a healthy reaction reflecting the adjustment of the organ to regular endurance training, a number of studies seem to suggest that high levels of endurance exercise can cause pathological changes to the structure of the heart. This was the conclusion reached by a team of Belgian cardiologists and sports medicine physicians in a study published in 2012 that received considerable global attention. 

The researchers established a link between extreme endurance exercise training and the acute enlargement and functional impairment of the right ventricle immediately after exercise. More precisely, they observed enlargement and reduced functionality of the right ventricle in athletes who had taken part in several hours of competitive endurance sport. However, longitudinal studies have so far failed to confirm the hypothesis formulated by the authors that endurance exercise results in long-term damage to the right ventricle, now referred to as 'exercise-induced arrhythmogenic right ventricular cardiomyopathy' (ARVC). It was therefore not clear whether the acute enlargement of the right ventricle after extreme endurance activity, which the Belgian group had identified and which had been frequently discussed among professionals, actually did lead to a potentially life-threatening chronic condition.

For the Saarbrücken research team led by cardiologist and sports medicine physician Prof. Dr. Jürgen Scharhag and Dr. Philipp Bohm, the hypothesis that endurance exercise leads to the pathological enlargement of the right ventricle was not immediately obvious. Scientists at the Saarbrücken Institute of Sports and Preventive Medicine have for years been examining elite athletes from a wide variety of disciplines, including triathletes, swimmers and professional footballers. In all that time, the Saarbrücken researchers never found any evidence underpinning the hypothesis posited by the Belgian team. They therefore decided to test the hypothesis explicitly.

They examined 33 elite master athletes (average age: 47) and compared them to a control group of 33 men who were similar in terms of age, size and weight but who had not done any kind of endurance exercise. The group of athletes, which included former Olympians as well as previous Ironman participants and champions, have been training at an elite level for around 30 years and still continue to train for an average of about 17 hours a week.

The Saarbrücken scientists were able to confirm that the hearts of these athletes, who have been engaged in elite level endurance activities for many years, were, as expected, significantly larger and stronger than those of members of the control group. 'But we found no evidence of lasting damage, pathological enlargement or functional impairment of either the right or left ventricle in the athletes who had been doing long-term intensive elite-level endurance exercise,' explains Philipp Bohm, who is now working at the Cardiology Centre at the University Hospital Zürich.

By focusing on highly trained and active elite master athletes, the Saarbrücken research team found a clever means of circumventing a problem faced by researchers interested in these questions. Although cardiovascular magnetic resonance imaging (cardiac MRI) is the best method of examining the heart and, in particular, the right ventricle, it has not been available for very long and it is not a routine technique for examining athletes. Systematic long-term MRI-based studies of athlete hearts will therefore not be available in the foreseeable future. Data from longitudinal studies, in which subjects have been monitored by MRI for years, potentially decades, simply does not exist. 'Our cohort of elite master athletes therefore represents our best means of investigating the long-term impact of years of competition-level endurance sport,' explains Jürgen Scharhag.