Health News: Green Tea Lowers Cholesterol; Gum Disease Affects Fertility; Vitamin D and Muscle Injuries

Michael Downey September 1, 2011

GREEN TEA LOWERS CHOLESTEROL

Researchers have completed a comprehensive meta-analysis, or review of previously done studies, and have found that drinking green tea or taking green tea extract lowered blood levels of total cholesterol, reducing levels of low-density-lipo-protein (LDL or bad) cholesterol, but with no effect on levels of high-density-lipoprotein (HDL or good) cholesterol. (LDL cholesterol is often referred to by the media as bad cholesterol because some studies have associated higher levels of these fat particles in the blood with health problems and cardiovascular disease.) The effect of green tea on cholesterol has been controversial. The combined results of 14 trials involving a total of 1,136 test subjects showed an average reduction in total cholesterol of 7.20 mg/dL, and an average reduction in LDL cholesterol of 2.19 mg/dL, both of which are considered statistically significant. This study was released June 29, 2011 by the American Journal of Clinical Nutrition and will appear in a future print issue.

GUM DISEASE CAN AFFECT FERTILITY

New research has found a strong link, primarily for non-Caucasian women, between periodontal disease and impaired fertility, and has confirmed known links between impaired fertility and being overweight, smoking, and being over the age of 35. (With impaired fertility, it takes months longer to achieve pregnancy. Periodontitis is caused by microorganisms that adhere to, and grow on, the tooth surface, combined with an overly aggressive immune response against these microorganisms.)

The underlying reason for the difficulty, among those suffering from periodontal disease, to become pregnant is believed to be the inflammatory response that develops in response to the disease. Non-Caucasian women were far more likely to have impaired fertility as a response to gum disease than Caucasian women because these women have a higher degree of inflammatory response. It was suggested that non-Caucasian women see a dentist to have periodontal disease treated prior to attempting pregnancy. (Treatment does not affect the health of the baby and often requires about four dentist visits.) This study was presented July 6, 2011 in Stockholm at the annual meeting of the European Society of Human Reproduction and Embryology. It has not yet been published, or posted online.

BELOW-OPTIMUM VITAMIN D LEVELS INCREASE MUSCLE INJURY RISK

New research has found that deficient and insufficient vitamin D levels in the blood may increase the risk of muscle injuries among athletes. The study analyzed levels in the blood of 89 professional NFL football players, and found their vitamin D concentrations broke down this way: 16 had sufficient levels, defined by the researchers as more than 32 nanograms per milliliter (32 ng/ml); 45 had insufficient (sub-optimum) levels, defined as 20-31.9 ng/ml; and 27 had deficient levels, defined as less than 20 ng/ml. Sixteen of the 89 players suffered a muscle injury and the average vitamin D level for these injured players was 19.9 ng/ml, suggesting that both insufficiency and deficiency raised the risk of muscle injury. The study recommended screening for vitamin D insufficiency among professional athletes to help prevent injuries. However, further research would be needed to determine whether increasing vitamin D levels would lead to improved muscle function. This study was presented July 10, 2011 in San Diego at the annual meeting of the American Orthopaedic Society for Sports Medicine (AOSSM).

MUSCLE MASS TRAINING LOWERS DIABETES RISK

A landmark study has concluded that the greater the muscle mass of an individual, the lower is his/her risk of developing insulin resistance and pre- or overt diabetes mellitus. This study underscores a little known fact: despite the truth that obesity is extremely common among patients when they are first diagnosed with diabetes, many thin people do get diabetes, especially among the elderly. This study has shown that low muscle mass, which is common to both the obese and the slender, is the actual risk factor, not weight.

In this research on 13,644 people, scientists graded subjects by their degree of insulin resistance, prediabetes, or diabetes. The grading up the scale from healthy to fully diabetic corresponded well with decreasing levels of overall muscle mass. In fact, every increase of 10% in muscle mass produced an 11% reduction in insulin resistance, and a 12% reduction in diabetes. This relationship held even after accounting for other factors. This suggests that it is muscle training that lowers diabetes risk, not the aerobic exercise often advised for cardiovascular benefit, and it is possible at any age to use muscle mass training to lower diabetes risk, and to improve existing diabetes. Also, it is not overall weight that counts, but ratio of muscle to weight: you can be overweight and still muscled enough to avoid diabetes. This study was released early and will not appear in print until a future issue of the Journal of Clinical Endocrinology & Metabolism.

HIGHER POTASSIUM INTAKE LINKED TO LOWER RISK OF DEATH

A study suggests that a higher intake of the element potassium lowers the risk of dying from any cause by 20%; and that compared to the quarter of the population with the lowest sodium-to-potassium intake ratio, the quarter with the highest sodium-to-potassium intake ratio has a 46% greater risk of dying from any cause and more than double the risk of dying from ischemic heart disease. The research confirms known links between higher sodium intake and cardiovascular disease (CVD), but also suggests that maintaining a higher ratio of potassium to sodium may reduce the risk of CVD and all-cause mortality. The results of this 15-year, 12,267-participant study were consistent regardless of race, body mass index, age, blood pressure, or physical activity. (In a varied diet, fruit is the greatest source of potassium.

In 2004, the Institute of Medicine recommended 4,700 mg of potassium daily; most Americans consume only half that amount; U.S. law limits the amount of potassium that non-prescription supplements can contain to 99 mg.) This study was published July 11, 2011 in the Archives of Internal Medicine.

SENSE OF OPTIMISM PROTECTS SENIORS FROM STROKE

Researchers have found that, among people aged 50 years and older, every unit higher that an individual scores on an optimism scale ranging from 3 to 18 (with higher scores indicating greater optimism) results in a 10% lower risk of having a stroke. In other words, if one person scored 7 and another more optimistic person scored 12, the second person would have, compared to the first, a 50% lower risk of having a stroke.

In the two-year study, the researchers accounted for psychological, biological and behavioural differences, as well as age and health, so that the stroke-protective effect was due strictly to the sense of optimism itself. The results suggest that the effect which optimistic attitude has on health is distinctly separate from any other psychological element such as happiness or emotional well-being. The scientists believe corroborating studies could lead to optimism interventions as a stroke prevention therapy. Optimism was assessed by employing the Life Orientation Test-Revised. This study was released late on July 21, 2011; it will be published in the October 2011 issue of the journal Stroke.

VITAMIN D SUFFICIENCY MAY HELP PREVENT ALZHEIMER’S DISEASE

Researchers have concluded that vitamin D sufficiency helps remove amyloid-beta plaque from the aging brain, across the blood-brain barrier, helping to prevent the excessive buildup that causes Alzheimer’s disease. (The build-up in the brain of amyloid-beta plaque is ordinarily controlled by transporter proteins and vitamin D. Although levels of these protein transporters increase with age, production tends to fail eventually. Low levels of vitamin D have been linked with age-related declines in memory and cognition, and with an increased risk of Alzheimer’s.) The team found that vitamin D injections in mice appear to help regulate protein expression and cell signaling, which helps prevent plaque buildup and the onset of Alzheimer’s disease and dementia. The implication is that maintaining sufficient vitamin D levels with advancing age may provide some preventive benefit, and a potential therapy, for these brain disorders. This newly released study will be published in a future issue of the journal Fluids and Barriers of the CNS. It is available early at https://bit.ly/nmFQyC without fee.

HUMAN BENEFIT FROM RESVERATROL – FURTHER STUDY SUGGESTED

Following their research review of the limited number of studies conducted so far that have relevance to humans, researchers have suggested that, although the polyphenol compound known as resveratrol may not prevent or retard actual aging, it may indeed help prevent some of the chronic conditions associated with old age, although more long-term human studies are urgently needed. Despite an abundance of evidence pointing to the beneficial effects of resveratrol, a compound found in grapes and wine, very few studies have been done on humans, and the bioavailability of resveratrol in humans, as opposed to animals, is still in doubt. Gathering together evidence from previous studies on animals, cultures and enzymes, the team found indication that resveratrol may have anti-oxidant, anti-cancer, and anti-inflammatory effects. The scientists suggested that, if the ability of resveratrol to alleviate age-related infirmities is established in humans, it could have vast importance as the baby boomer generation enters old age. This just-released study will appear in a future issue of the journal Molecular Nutrition & Food Research.

SMOKERS HAVE HIGHER RISK OF PROSTATE CANCER RECURRENCE AND DEATH

A study has found that smokers who develop prostate cancer have a 61% greater risk of a recurrence after treatment, and a 61% higher risk of dying from prostate cancer, compared to nonsmokers diagnosed with prostate cancer. Researchers also found that smokers who are initially diagnosed with non-metastatic prostate cancer have an 80% greater risk of dying from this disease than nonsmokers. A link was also found between smoking and more aggressive forms of prostate cancer. Smokers who were diagnosed with prostate cancer also showed a 131% higher risk of dying from cardiovascular disease. However, men who had quit smoking for 10 years or more prior to being diagnosed with prostate cancer had the same level of risk as nonsmokers. Prostate cancer is the most frequently diagnosed form of cancer in the U.S. The team stressed that quitting smoking directly reduces the risk of dying from prostate cancer. This study will be published in the June 22-29, 2011 issue of the Journal of the American Medical Association.

TYPE 2 DIABETES REVERSED WITH EXTREME DIET

A small but landmark study has found that Type 2 diabetes patients who followed an extreme but tightly supervised diet that restricted calories to just 600 a day, for two months, experienced a return to normal pre-breakfast blood sugar levels after one week, and that 70% of those patients remained completely free of diabetes a month after returning to their regular, but newly portion-controlled, diet. (Type 2 diabetes is a condition in which blood sugar levels are too high due to insufficient insulin or the inability to use insulin effectively.) The researchers believe excess calories eventually cause fat buildup in the liver and pancreas, triggering Type 2 diabetes. MRI scans of study subjects showed the pancreas returns quickly to normal fat levels and regains its ability to produce insulin. This suggests Type 2 diabetes may be reversed by calorie restriction alone. A 600-calorie diet is a drastic starvation diet that should only be followed temporarily and only under close practitioner supervision. Presented at the June 24-28, 2011 American Diabetes Association conference, this study will appear in a future issue of the journal Diabetologia, but is now accessible online for free.

COMPARED TO SHELLED, IN-SHELL PISTACHIOS CUT CALORIES SUBSTANTIALLY

In two separate studies in the same journal, researchers have concluded that shelling and eating pistachios reduces calorie intake by 41% compared to eating pistachios that have already been shelled. This suggests that the sight of, and opening of, the shells themselves give visual clues that serve as a mindful benefit that curbs overeating. In one study, those who ate shelled pistachios consumed an average of 211 calories while those who ate the in-shell nuts took in only 125 calories.

In the second study, more pistachios were eaten by those whose discarded shells were removed every two hours, than by those whose discarded shells were left in sight all day. (Another study released in June 2011 found that the fat in pistachios is not fully absorbed by the body, meaning that they may involve ingestion of fewer calories than previously thought. At 160 calories per ounce, or per 30 grams, pistachios are lower in calories compared to other nuts.) This just-released study will not be published in print until the October 2011 issue of the journal Appetite.

KEY CAUSE OF AGING DETERIORATION CAN BE CORRECTED

A study has found that a diminished capacity to manufacture glutathione (GSH) explains the observed lower levels in, and is a key factor in, age-related deterioration – and that supplementation with two GSH precursors restores normal levels, diminishing age-related damage. (GSH is a primary antioxidant, crucial to completing the antioxidant process started by other antioxidants, and without which half-finished metabolism of free radicals causes a chain reaction of cell destruction.) Reduced GSH levels occur with age, damaging cells, but the reason for the drop has been unclear. This new study showed that age-related reductions in GSH levels stem from diminished ability to synthesize GSH. Supplementing with the GSH precursors cysteine and glycine fully restored normal GSH production, largely restored normal GSH concentration levels, and significantly reduced oxidative stress and the cellular damage of aging. The report suggested supplementation with cysteine and glycine may be a safe and effective way to lower age-related free radical damage. (The body cannot directly absorb GSH well.) This study was released July 27, 2011 by the American Journal of Clinical Nutrition but will not be published until a future issue. It is available online with subscription or fee.

CHEMICAL PRODUCED BY PANCREAS MAY CURE TYPE 1 DIABETES

A study has found that injection of gamma-aminobutyric acid (GABA), a compound that is produced in non-diabetic people by the same pancreatic cells (islet beta cells) that normally make insulin, can prevent and even reverse Type 1 diabetes in mice. (In Type 1 diabetes, formerly known as juvenile diabetes, the immune system attacks and destroys the beta cells in the pancreas that make and secrete insulin, leaving the patient with little or no insulin.

GABA is also known as a brain messenger, or neurotransmitter, but its role in the pancreas was unknown.) This may be an especially effective therapy and prevention for Type 1 diabetes because GABA was found both to regenerate insulin-producing beta cells and to prevent destruction of those cells by the immune system. This treatment would need human trials before it could be considered a new treatment for Type 1 diabetes. This study was released June 27, 2011 and will appear in a future issue of the Proceedings of the National Academy of Science. It is available online with subscription or fee.

RESVERATROL MIGHT OFFSET SEDENTARY LIFESTYLE

A study has suggested that resveratrol, a compound found in small amounts in cocoa powder, boiled peanuts, and red wine, may offset the negative health effects – such as insulin resistance and loss of bone mass – stemming from a lack of exercise in a sedentary lifestyle. (Resveratrol is an antioxidant substance known as a phenol. It is often reported by the mainstream media to be a major component of red wine; in fact, wine contains only trace amounts. Its cardiovascular health benefits are controversial and the subject of ongoing research.) The researchers tested resveratrol on rats that lived in an environment mimicking the weightlessness of space, which has negative health effects on astronauts. The rats provided with resveratrol managed to avoid the insulin resistance and loss of bone mineral density that affected those sedentary rats not fed resveratrol. (Insulin resistance is linked to diabetes risk.) Resveratrol is found in supplements (which are often made from Japanese knotweed) and in small amounts in cocoa powder, red wine, and boiled peanuts. This study was released June 29, 2011 and will appear in a future issue of The FASEB Journal. It is available online with subscription or fee.

MOST EIGHT-MONTH-OLDS CONSUMING EXCESSIVE SALT

A study reports that 70% of babies who are just eight months old are already consuming levels of sodium chloride (salt) that exceed the dietary recommendations, at least in the U.K. where the study was completed, and the problem may be establishing a lifelong taste for salty foods in these children, and could damage young kidneys. (Babies up to 12 months should not ingest more than 400 mg of sodium daily.) The report found that 70% of eight-month-olds are primarily getting excess salt due to consumption of processed adult foods and cow milk. Cow milk contains more sodium, at 55 mg per 100 gm, than breast milk, which contains only 15 mg per 100 gm, or formula, which holds 15 to 30 mg per 100 gm, and the research team stressed that milk from cows not be given prior to two years of age. Also, adult processed foods are regularly given to babies, according to the report, in the form of a large amount of bread, gravy, canned spaghetti, and baked beans. The study used figures on babies born in 1991 and 1992, but scientists doubt that wholesale changes have since taken place in the feeding of 8-month olds. Just released by the European Journal of Clinical Nutrition, this study is available online.

GRAPESEED POLYPHENOLS MAY PREVENT ALZHEIMER’S DISEASE

A new study has found that grapeseed polyphenol, a natural antioxidant, suppresses the creation of a specific form of beta-amyloid peptide – a substance in the brain long known to cause the neurotoxicity associated with Alzheimer’s disease – and therefore confirms, according to the researchers, previous research suggesting that grapeseed polyphenol may be an effective treatment for people at risk for the disease to prevent its development or retard its progression.

The authors stress that for grape-derived polyphenols to be effective, it will be necessary to find a biomarker for those at risk, although it may also be beneficial for those in the early stages of this memory-robbing disease. The study is significant because it is the first to examine the effect of this substance on these destructive peptides, illustrating the mechanism behind the apparent protective benefit, and because it was conducted on living subjects, namely mice. However, research is now being conducted to confirm that the results hold true for humans. The full-text of this just-released study is not yet available but will be published in a future issue of the Journal of Alzheimer’s Disease.

FACTOIDS OF INTEREST

Your body makes better use of vitamin D supplements if you take them with your largest meal. According to a Cleveland Clinic study reported in the April 2010 issue of the Journal of Bone and Mineral Research, this will boost its uptake, over a three-month period, by up to 56%.

According to the Centers for Disease Control and Prevention (CDC), over 50 million unnecessary antibiotic courses are prescribed in the U.S. annually for viral respiratory infections. However, antibiotics have no impact on viral respiratory infections, and excess use can result in strains of bacteria, normally susceptible to antibiotics, that are antibiotic resistant.
It is extremely difficult to spread a cold or the flu by kissing, even kissing babies. Saliva in the mouth harbours very little virus material. However, coughing is a different matter, because it brings forth virus-laden fluids from deep within the lungs. Cover your mouth when you cough.
The risk of hyperthermia, the condition in which the body overheats in hot weather, increases as we age, due to age-related changes in the skin, such as decreased functioning of the sweat glands and small blood vessels. This reminder and tips to avoid hyperthermia were issued by the National Institutes of Health recently.
In at least one study, alcohol was only barely related to the risk of cirrhosis. Being overweight (a BMI of 28 or more) and having high triglycerides were each far greater risk factors. This research was published in the June 2011 issue of the Scandinavian Journal of Gastroenterology.
Anyone who consumes a cooked weight of 90 grams of red meat or processed meat per day has a significantly higher risk of developing bowel cancer compared to those who eat 70 grams or less. On February 26, 2011, the British Department of Health advised people to keep red meat consumption at 70 grams a day. Men tend to eat more red or processed meat than women.
A number of studies link sufficient levels of vitamin D with a reduced risk of colorectal, breast, prostate, and pancreatic cancers, although some large studies have shown conflicting results. About one-third of Americans are not getting enough vitamin D, according to a March 2011 report from the Centers for Disease Control and Prevention, and the elderly are often vitamin-D deficient. Canadians have higher rates of deficiency as well as a higher cancer rate.