News Briefs – November 2015

CONSUMPTION OF A MEDITERRANEAN DIET IS ASSOCIATED WITH PREVENTION OF THE ONSET OF DEPRESSION

Mediterranean Diet Reduces Risk of Depression

New research has found that eating a Mediterranean diet (or any similarly healthy dietary pattern comprised of fruit, vegetables, legumes, and nuts, and low in processed meats) is associated with prevention of the onset of depression. This large study of 15,093 people suggests depression could be linked with nutrient deficits.

Following extensive research into diet and its effect on our physical health, researchers are now exploring the link between nutrition and mental health. This is the first time that several healthy dietary patterns and their association with the risk of depression have been analyzed together.

The researchers compared three diets; the Mediterran-ean diet, the Pro-Vegetarian Dietary Pattern, and the Alternative Healthy Eating Index-2010. The Alternative Healthy Eating Index-2010 and the Mediterranean Diet showed the lowest risk of depression, but these diets share many similarities, including omega-3 fatty acids, vegetables, fruits, legumes, nuts and moderate alcohol intake. The study showed that even a moderate adherence to these diets was associated with reduced risk of developing depression; researchers observed no extra benefit when participants showed high or very high adherence to the diets. This is consistent with the hypothesis that suboptimal intake of some nutrients may be a risk factor for depression; but once the threshold is achieved, increased intake of these nutrients does not reduce the risk further.

This study was published on Sept. 17, 2015 by the journal BMC Medicine and is available now at https://tinyurl.com/po9kuzb

Certain Probiotics Linked to Reversal of Milk Allergy

New research has found that infants developed tolerance to their cow milk allergy after treatment with a probiotic formula. Furthermore, their gut bacteria showed significant differences from those infants who remained allergic. The newly tolerant infants had higher levels of several strains of bacteria that produce short chain fatty acids, such as butyrate, which help maintain homeostasis (a balanced state) in the gut. The discovery of bacteria that drive tolerance to allergy-triggering foods such as milk could be critical to developing new treatments to help children with food allergies. (There has been an unprecedented increase in food allergies in developed countries, rising by as much as 20% in the past decade. Allergy to cow milk is one of the most common, occurring in up to 3% of children worldwide.)

It was shown that infants treated with formula containing the probiotic bacterial species Lactobacillus rhamnosus GG (LGG) and who developed tolerance to cow milk had higher levels of bacteria that produce butyrate than those who were fed the probiotic formula but did not develop tolerance. In addition to LGG, this further suggests that tolerance is linked to the acquisition of specific strains of bacteria that produce butyrate, which include Blautia and Coprococcus. Future studies may confirm this as a therapy for allergies to foods such as milk.

This study was released on September 22, 2015 in the advance online publication section of the ISME Journal. You can access the full study report now at https://tinyurl.com/qjryq33 free of charge.

Did You Know…?

A JAMA Psychiatry study showed that marijuana use in adolescence works to thin, and disrupt the maturing of, the cerebral cortex in the brain and increases the risk of schizophrenia later in life.

Vitamin D Deficiency Confirmed in Development of Multiple Sclerosis

A long-known association between vitamin D deficiency and incidence of multiple sclerosis (MS) has now been confirmed to be a cause-and-effect link. (MS is a chronic disease that affects about 2.3 million people worldwide and can cause blurred vision, slurred speech, tremors, extreme fatigue, memory problems, paralysis, and blindness. There is no known cure.) Previous observational studies found an association between the level of vitamin D, which comes from sunlight and certain foods, and MS. But the problem with these studies was that they could not prove that low vitamin D actually caused MS; they may have been showing simply that people who were sick with MS tended to stay inside more and get less sunlight. The latest study got around that obstacle by analyzing the association between genetically reduced vitamin D levels and the likelihood of MS in a pool of 14,498 MS patients and 24,091 healthy controls. This way, the lower vitamin D levels are known to have existed before MS developed.

The results showed that babies born with genes associated with vitamin D deficiency are twice as likely as other babies to develop MS as an adult. This indicates that either low vitamin D triggers MS or that there are other complex genetic interactions. The researchers do not yet know if giving healthy children and adults vitamin D supplements will decrease their risk of developing MS, but clinical trials are being conducted now to study this nutritional approach.

This study was released August 25, 2015 by the journal PLoS Medicine and can be accessed at https://tinyurl.com/o72av52 free of charge

Scientists Pinpoint Why Vegan or Med Diets are Superior for Health

New research has identified the underlying mechanism for the often-reported health benefits of vegan, vegetarian, and Mediterranean diets. Of the 153 people taking part, 51 were omnivores, 51 were vegetarians, and 51 were vegans. A Mediterranean diet was found to include 88% of what vegans ate, 65% of what vegetarians ate, and 30% of what omnivores ate. (The Mediterranean diet is high in fibre-rich fruits, vegetables and legumes, compared with an Anglo-Saxon diet that includes a lot of red meat and dairy products.)

The researchers found that there were distinctly different patterns of intestinal microbial activity for various eating patterns. They found a direct link between the amount of fibre-rich foods consumed and the production in the gut of important, health-promoting, short-chain fatty acids (SCFAs). SCFAs are produced when fibre from dietary plant matter is fermented in the colon. Healthful SCFAs include acetate, propionate, and butyrate. Butyrate, for example, is the primary energy source for colonic cells, making it vital to colon health, and it has anti-carcinogenic and anti-inflammatory properties. SCFAs are the connection, the study concludes, to health benefits of vegan, vegetarian, and Mediterranean diets, which include reducing the risk of inflammatory disease, diabetes, and heart disease. Beneficial microbial activity differed by diet: those who ate a predominantly plant-based diet, particularly vegans, had higher levels of Bacteroidetes in their gut; those who ate a predominantly animal-based diet had higher levels of Firmicutes. Differing microbial species in these different categories of organism, known as phyla, are better able to break down complex carbohydrates resulting in the all-important production of SCFAs.

Levels of a compound linked to cardiovascular disease, called trimethylamine oxide (TMAO), were far higher in meat-eaters than in vegetarians and vegans. Sources of trimethylamine, which the liver converts into TMAO, include eggs, beef, pork, and fish. It turns out that the overall quantity of fruit, vegetables, legumes, and fibre that is consumed matters far more to the production of SCFAs, and consequent health benefits, than the specific overall food groups in any dietary regime followed.

This study will be published in a future issue of the journal Gut. However, it can be accessed online now at https://tinyurl.com/potw4k3 for an access fee.

Vitamin C as Effective as Exercise for Improving Vascular Health in the Obese

A small study has concluded that vitamin C supplementation reduces the blood vessel constriction that is present in overweight and obese adults. Vitamin C was found to be equally as effective as exercise. (Exercise has been shown to reduce endothelin-1 activity, but including it in a daily routine can be challenging. Vitamin C supplements may be a simple alternative.) The study of 35 obese or overweight adults compared the effects of vitamin C and exercise on the protein known as endothelin-1, which has a constricting action on small blood vessels. The activity of this protein is raised in overweight and obese people, and because of this small blood vessels are more prone to constricting, becoming less responsive to blood flow demand, and increasing the risk of vascular disease.

Twenty overweight or obese adults completed three months of time-release 500 mg vitamin C supplementation while 15 participants followed three months of aerobic exercise training. The reduction in vasoconstriction resulting from Vitamin C supplementation was as much as the reduction in vasoconstriction resulting from aerobic exercise. (Previously, it was reported that vitamin C may help prevent colds in people under heavy physical stress such as marathon runners.)

The study was presented September 5, 2015 in Savannah at the American Physiological Society’s 14th International Conference on Endothelin.

25-Minute Daily Walk Adds 7 Years to Life Span

A study has reported that a brisk, 25-minute, daily walk can cut the risk of dying from a heart attack in half and can add seven years to life span. Even those who don’t start walking until the age of 70 can still reap benefits, including lowering their odds of developing atrial fibrillation. Researchers studied a group of inactive but healthy people who began an exercise program. After six months, blood tests showed that all forms of exercise, including aerobic exercise, endurance exercise, high-intensity interval training, and strength training, had positive effects on the markers of aging, including the repair of old DNA. Endurance and high-intensity interval exercise were most beneficial. A brisk walk was shown to be as beneficial as many other exercise types, was least likely to result in injury, was easiest for the aged or those with heart or other issues, and the most likely to be continued. The lead researcher suggested that everyone walk at least 20 to 25 minutes every day.

According to the lead researcher, following this simple routine may retard the process of aging and extend life span. This study was recently presented in London at the European Society of Cardiology Congress.

Low-Dose Fish Oil Improves Arthritis Better Than High-Dose

A surprising new study reports that low doses of fish oil fight arthritis pain better than higher doses. Scientists enrolled 202 patients suffering from osteoarthritis of the knee. One group received 4.5 grams of omega-3 fatty acids (EPA and DHA) daily for two years, while a second group took 0.45 grams of omega-3 fatty acids (EPA and DHA) daily for the same period. (Osteoarthritis of the knee is a common problem that develops with aging and injury. Research has found that taking omega-3 fatty acids in the form of fish oil supplements can lower inflammation, decrease pain, and improve function. Until now, no study has compared the differential effects of different dosages.)

Both groups experienced some improvement. But the low-dosage group showed greater improvement at three, six, 12, and 24 months in both the pain and function, measured on the standard test known as the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Further study is needed to evaluate the reason for this difference.

This study was posted online September 9, 2015 by the Annals of Rheumatic Diseases. It will be published in the journal at a later time. The full report can be read at https://tinyurl.com/q34egg2 for an access fee.

Common Cattle Virus May Be a Cause of Breast Cancer

For the first time, scientists have found a potential link between a virus found in dairy and beef cattle and human breast cancer. The virus is called bovine leukemia virus (BLV). It infects the blood cells and mammary tissue of cattle. The study analyzed breast tissue from 239 women, comparing samples from those women who had breast cancer with women who had no history of the disease for the presence of BLV. They found that 59% of breast cancer samples had evidence of exposure to BLV, as determined by the presence of viral DNA. By contrast, 29% of the tissue samples from women who never had breast cancer showed exposure to BLV. (If BLV were proven to be a cause of breast cancer, it could change the way we currently look at breast cancer control, shifting the emphasis to prevention of breast cancer, rather than trying to cure or control it after it has already occurred.)

When the data was analyzed statistically, the odds of having breast cancer if BLV were present were 3.1 times greater than if BLV was absent. This odds ratio is higher than any of the frequently publicized risk factors for breast cancer such as obesity, alcohol consumption, and use of post-menopausal hormones. It is critical to note that these results do not prove that the virus causes cancer. Researchers still need to confirm that the BLV infections developed before, not after, the breast cancer developed, and if so, how. The virus is likely passed to humans via milk or beef. (A study published last year overturned a long-held belief that this virus, which is extremely common among cattle, could not be transmitted to humans. Because it was still difficult to overturn the established dogma that BLV was not transmissible to humans, there has been little incentive for the cattle industry to set up procedures to contain the spread of the virus. There is precedence for viral origins of cancer. Hepatitis B virus is known to cause liver cancer, and the human papillomavirus can lead to cervical and anal cancers.)

This study was published online in September 2015 by the journal Plos ONE. The full study can be downloaded at https://tinyurl.com/ojkxuwk free of charge.

Sugary Drinks Boost Fatal Heart Disease Risk by More Than a Third

Researchers have reported new findings that sugar-sweetened beverages increase the risk of diabetes, heart disease and stroke, including a 35% greater chance of developing a fatal heart disease. (Half the population consumes sugar-sweetened drinks daily, despite evidence they lead to weight gain, obesity, and increased risk of disease. This is partly because liquid calories are not filling, which means that people drink them alongside their usual food intake.)

Beverages containing added sugars in the form of high-fructose corn syrup (made from corn starch) or sucrose (table sugar) were the focus of this review of previous meta-analyses, which also investigated exactly how fructose may contribute to negative effects. Analysis showed that one or two servings of a sugary beverage daily increase the risk of developing Type 2 diabetes by 26%, heighten the risk of heart attack or fatal heart disease by 35%, and raise the risk of stroke by 16%. Investigation also showed that unlike glucose, which is directly absorbed into the bloodstream through the gastrointestinal tract to provide fuel, fructose is metabolized in the liver, where it can be converted to fatty compounds called triglycerides. This can lead to fatty liver disease as well as insulin resistance. (Fatty liver is a risk factor for cardiovascular disease.) Fructose can also cause an increase in uric acid in the blood, leading to gout, a painful inflammatory arthritis.

The scientists suggested water, tea, or coffee as alternatives but urged caution regarding artificially sweetened drinks, since the long-term effects of these are not yet known. The WHO and the 2015 US Dietary Guidelines Advisory Committee both recommend that added sugars comprise no more than 10% of total calories consumed.

This study was published in the October 6, 2015 issue of the Journal of the American College of Cardiology. However, you can read the full study now at https://tinyurl.com/oosyw3p for a fee.

Did You Know…?

The average radiation to which nuclear bomb victims in Hiroshima and Nagasaki were exposed boosted their risk of dying from lung cancer by about 40%. But smoking a pack of cigarettes daily boosts the risk of dying of lung cancer by about 400%.

Vitamin D Assists Women to Build Muscle After Menopause

A study now documents that vitamin D supplementation can significantly increase muscle strength and reduce the age-related loss of body muscle mass in women even as late as 12 or more years after menopause. (The benefits of vitamin D supplementation for postmenopausal women have been widely debated. Vitamin D deficiency is a common problem in postmenopausal women, creating muscle weakness and a greater tendency to fall.) The double-blind, placebo-controlled trial was conducted over a nine-month period. Muscle mass was estimated by total-body DXA (dual energy X-ray absorptiometry), as well as by hand-grip strength and through a chair-rising test. At the end of the trial, the women receiving the supplements demonstrated a significant increase in muscle strength of over 25%, while those receiving the placebo actually lost an average of 6.8% of muscle mass. Women not receiving Vitamin D supplements were also nearly two times as likely to fall.

The study results will be presented at the 2015 Annual Meeting of the North American Menopause Society, which begins September 30 in Las Vegas.

Scientists Raise Alarm Regarding Endocrine-Disrupting Chemicals

Although not a journal-reported study, a Scientific Statement was issued September 28, 2015 by the Endocrine Society, announcing that emerging evidence ties endocrine-disrupting chemical (EDC) exposure to two of the biggest public health threats facing society: diabetes and obesity. Release of the official statement came as society experts were addressing the International Conference on Chemicals Management (ICCM4) in Geneva on the importance of using scientific approaches to limit health risks of EDC exposure.

Further to information known when the society produced its groundbreaking 2009 report, which examined the state of scientific evidence on endocrine-disrupting chemicals (EDCs) and the risks posed to human health, additional research has found that exposure is associated with increased risk of developing diabetes and obesity. Mounting evidence also indicates EDC exposure is connected to infertility, hormone-related cancers, neurological issues, and other disorders.

The statement warns that EDCs contribute to health problems by mimicking, blocking, or otherwise interfering with natural hormones. By hijacking these chemical messengers, EDCs can alter the way cells develop and grow. Known EDCs include bisphenol A (BPA) found in food can linings and cash register receipts, phthalates found in plastics and cosmetics, flame retardants (often used in furniture, carpet, and draperies), and pesticides. The chemicals are so common that nearly every person on Earth has been exposed to one or more.

The threat is particularly great when unborn children are exposed to EDCs. Animal studies found that exposure to even tiny amounts of EDCs during the prenatal period can trigger obesity later in life. Similarly, animal studies found that some EDCs directly target beta and alpha cells in the pancreas, fat cells, and liver cells, which can lead to insulin resistance. Most of these studies point to an association but do not determine EDCs actually cause disease, yet the number of corroborating studies continues to mount.

The statement calls for studies that would show cause-and-effect and for regulation to ensure that chemicals are tested for endocrine activity before being permitted for use. The Endocrine Society provides more information about EDC’s and other matters at https://endocrinefacts.org

Did You Know…?

A study found that children whose mothers took antibiotics during pregnancy were almost twice as likely to develop asthma as children whose mothers did not. Although researchers have known this since at least 2012, a recent magazine article summarizes this topic: read the summary at https://tinyurl.com/q7rq2d4