All Posts tagged diet

Pecans Can Prevent Heart Disease

A new research study from Loma Linda University (LLU) demonstrates that naturally occurring antioxidants in pecans may help contribute to heart health and disease prevention; the results were published in the January 2011 issue of The Journal of Nutrition.

Pecans contain different forms of the antioxidant vitamin E — known as tocopherols, plus numerous phenolic substances, many of them with antioxidant abilities. The nuts are especially rich in one form of vitamin E called gamma-tocopherols. The findings illustrate that after eating pecans, gamma-tocopherol levels in the body doubled and unhealthy oxidation of LDL (bad) cholesterol in the blood decreased by as much as 33 percent. Oxidized LDLs may further contribute to inflammation in the arteries and place people at greater risk of cardiovascular problems. “Our tests show that eating pecans increases the amount of healthy antioxidants in the body,” says LLU researcher Ella Haddad, DrPH, associate professor in the School of Public Health department of nutrition. “This protective effect is important in helping to prevent development of various diseases such as cancer and heart disease.”

These findings are from a research project designed to further evaluate the health benefits of pecans, according to Dr. Haddad. She analyzed biomarkers in blood and urine samples from study participants (a total of 16 men and women between the ages 23 and 44) who ate a sequence of three diets composed of whole pecans, pecans blended with water, or a control meal of equivalent nutrient composition. The pecan meals contained about three ounces of the nut. Samples were taken prior to meals and at intervals up to 24 hours after eating. Following the test meals composed of whole pecans and blended pecans, researchers found that amounts of gamma-tocopherols (vitamin E) in the body doubled eight hours after both meals, and oxygen radical absorbance capabilities (ORAC — a scientific method for measuring antioxidant power in the blood) increased 12 and 10 percent respectively two hours after the meals. In addition, following the whole-pecan meal, oxidized LDL cholesterol decreased by 30 percent (after 2 hours), 33 percent (after 3 hours), and 26 percent (after 8 hours).

“This study is another piece of evidence that pecans are a healthy food,” says Dr. Haddad. “Previous research has shown that pecans contain antioxidant factors. Our study shows these antioxidants are indeed absorbed in the body and provide a protective effect against diseases.” Research from Loma Linda University published earlier in the Journal of Nutrition showed that a pecan-enriched diet lowered levels of LDL cholesterol by 16.5 percent — more than twice the American Heart Association’s Step I diet, which was used as the control diet in that study. Similarly, the pecan-enriched diet lowered total cholesterol levels by 11.3 percent (also twice as much as the Step I diet).

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Experts find clue to yo-yo dieting

Scientists may have discovered a way of identifying dieters who are prone to piling the pounds back on after weight loss. A study at Maastricht University’s Department of Human Biology found a link between a gene involved in regulating blood pressure and post-diet weight gain in women. Women who regained weight after slimming had a high change in the concentration of a particular protein in their blood during dieting, research showed. Researchers now hope to develop a test to indicate how prone people are to yo-yo dieting.

Edwin Mariman, professor of functional genetics at Maastricht, said: “It was a surprising discovery, because until now there has been no clear link between this protein and obesity. “We do not yet have an explanation for the results, but it does appear that it should be possible within a few years to use this finding to develop a test to show who is at high risk of putting weight back on after a diet.”

Hospitals already conduct tests for the protein, known as the angiotensin I converting enzyme (ACE). But the test is currently carried out to check its activity in regulating blood pressure, rather than its concentration. Up 80% of dieters suffer from the yo-yo effect, returning to their original weight within a year.

The study looked at around 100 women aged 20 to 45, half of whom had maintained their post-diet weight and half of whom had put weight back on. The findings of the research have been published by Dr Ping Wang, a scientist in Professor Mariman’s research group, in the online scientific journal PloS ONE.

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High fibre diet helps you live longer

Eating a diet rich in fibre has long been known to help keep your digestive tract working properly. It’s also thought to lower the risk of heart disease, some cancers and diabetes. Now, a new study suggests it could reduce the risk of death from cardiovascular, infectious and respiratory diseases. People who ate a high-fibre diet decreased their risk of dying over a nine year period compared to those who ate less fibre, according to a new study in the Archives of Internal Medicine.

The findings are based on a diet study from the National Institutes of Health and AARP, which included 219,123 men and 168,999 women ages 50 to 71 when the study began. Researchers from the National Cancer Institute examined food surveys completed by the participants in 1995 or 1996. After nine years about 11,000 people died and researchers used national records to determine the cause.

People who ate at least 26 grams per day were 22 percent less likely to die than those who consumed the least amount of fibre — about 13 grams per day or less. Men and women who consumed diets higher in fibre also had a reduced risk of cardiovascular, infectious and respiratory diseases, the study found. Getting fibre from grains seemed to have the biggest impact, the authors write.

The study has some limitations — mainly, people who ate high-fibre diets might also have been more likely to eat healthier diets overall, attributing to their longevity. Still, the study offers more evidence that fibre is certainly good for you. Federal dietary guidelines recommend people consume at least 14 grams of fibre per 1,000 calories, so about 28 grams for an average 2,000 calorie-per-day diet. But many experts say many people don’t get enough.

 

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Vegetarian diet helps with kidney disease

Chronic kidney disease (CKD) patients who consume a diet high in vegetables rather than meat may prevent the accumulation of toxic phosphorus levels, according to a study published online Dec. 23 in the Clinical Journal of the American Society of Nephrology.Sharon M. Moe, M.D., of the Indiana University School of Medicine in Indianapolis, and colleagues conducted a crossover trial in nine patients with a mean estimated glomerular filtration rate of 32 ml/min to compare vegetarian and meat diets containing equivalent nutrients prepared by clinical research staff.

The investigators found that one week of a vegetarian diet led to lower serum phosphorus levels, decreased phosphorus excretion in the urine, and reduced fibroblast growth factor-23 levels compared with a meat diet, despite equivalent protein and phosphorus concentrations in the two diets.

“In summary, this study demonstrates that the source of protein has a significant effect on phosphorus homeostasis in patients with CKD. Therefore, dietary counseling of patients with CKD must include information on not only the amount of phosphate but also the source of protein from which the phosphate derives,” the authors write.

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Antioxidants lower stroke risk

Eating a diet high in antioxidants may protect against ischemic stroke, an Italian cohort study showed.

People who had a diet high in total antioxidant capacity — an index that takes into account several different antioxidants and their interactions — had a 59% reduced relative risk of ischemic stroke (HR 0.41, 95% CI 0.23 to 0.74), according to Nicoletta Pellegrini, PhD, of the University of Parma in Italy, and colleagues. But there was no such relationship with hemorrhagic stroke, they reported in the January issue of the Journal of Nutrition. In fact, the highest intake of the antioxidant vitamin E was associated with a greater risk of hemorrhagic stroke (HR 2.94, 95% CI 1.13 to 7.62).
Considering evidence suggesting that oxidative stress and systemic inflammation are involved in the pathogenesis of ischemic stroke, the researchers noted that “a high-total antioxidant capacity diet could be protective as a consequence of its ability to deliver compounds with antioxidant activity and with a demonstrated anti-inflammatory effect.” But, they acknowledged that the mechanism for such activity was unclear may “go beyond the antioxidant activity of the numerous total antioxidant capacity contributors present in foods and beverages.”

Pellegrini and her colleagues set out to explore the relationship between dietary total antioxidant capacity and the risk of stroke among 41,620 people participating in EPICOR, the Italian segment of the European Prospective Investigation into Cancer and Nutrition (EPIC). None had a history of stroke or MI at baseline. Dietary intake was assessed with a food frequency questionnaire. In the study population, more than half of the total antioxidants consumed came from coffee, wine, and fruit. Through a mean follow-up of 7.9 years, there were 112 ischemic strokes, 48 hemorrhagic strokes, and 34 other types of strokes. After adjustment for energy intake, hypertension, smoking status, education, nonalcoholic energy intake at recruitment, alcohol intake, waist circumference, body mass index, and total physical activity, individuals eating a diet in the highest tertile of total antioxidant capacity had a reduced risk of ischemic — but not hemorrhagic — stroke.

Looking at individual antioxidants, the researchers found that participants consuming the highest amounts of vitamin C had a reduced risk of ischemic stroke (HR 0.58, 95% CI 0.34 to 0.99). Controlling for vitamin C intake did not negate the overall association between antioxidants and ischemic stroke, which ruled out the nutrient as the sole driver of the relationship. High intake of vitamin E, on the other hand, was associated with nearly triple the relative risk of hemorrhagic stroke. However, “it must be stressed that the small number of cases observed in this population strongly limits the validity of statistical observations on hemorrhagic stroke,” noted the researchers, who called for further studies.

Aside from anti-inflammatory effects, it is possible that the association between antioxidants and ischemic stroke risk can be explained by the interaction between polyphenols — the major contributors to total antioxidant capacity — and the generation of nitric oxide from the vascular endothelium. That interaction leads to the vasodilation and expression of genes that may be protective for the vascular system, according to the researchers. In addition, coffee — the main source of antioxidants in the study population — reduces blood pressure, which is a recognized risk factor for ischemic stroke, the researchers wrote.

They noted some limitations of the study, including the low numbers of cases when different types of stroke were analyzed, the measurement of total antioxidant capacity at baseline only, and the inability to rule out confounding effects of other dietary components, like sodium and potassium.

Source: Del Rio D, et al “Total antioxidant capacity of the diet is associated with lower risk of ischemic stroke in a large Italian cohort” J Nutr 2011; 141: 118-123.

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Garlic protection from Osteoarthritis

Researchers at King’s College London and the University of East Anglia have discovered that women who consume a diet high in allium vegetables, such as garlic, onions and leeks, have lower levels of hip osteoarthritis. The findings, published in the BMC Musculoskeletal Disorders journal, not only highlight the possible effects of diet in protecting against osteoarthritis, but also show the potential for using compounds found in garlic to develop treatments for the condition. A relationship between body weight and osteoarthritis was previously recognised, although it is not yet completely understood. This study is the first of its kind to delve deeper into the dietary patterns and influences that could impact on development and prevention of the condition.

Osteoarthritis is the most common form of arthritis in adults, affecting around 8 million people in the UK, and women are more likely to develop it than men. It causes pain and disability by affecting the hip, knees and spine in the middle-aged and elderly population. Currently there is no effective treatment other than pain relief and, ultimately, joint replacement.

The study, funded by Arthritis Research UK, the Wellcome Trust and Dunhill Medical Trust, looked at over 1,000 healthy female twins, many of whom had no symptoms of arthritis. The team carried out a detailed assessment of the diet patterns of the twins and analysed these alongside x-ray images, which captured the extent of early osteoarthritis in the participants’ hips, knees and spine. They found that in those who consumed a healthy diet with a high intake of fruit and vegetables, particularly alliums such as garlic, there was less evidence of early osteoarthritis in the hip joint.

To investigate the potential protective effect of alliums further, researchers studied the compounds found in garlic. They found that that a compound called diallyl disulphide limits the amount of cartilage-damaging enzymes when introduced to a human cartilage cell-line in the laboratory. Dr Frances Williams, lead author from the Department of Twin Research at King’s College London, says: “While we don’t yet know if eating garlic will lead to high levels of this component in the joint, these findings may point the way towards future treatments and prevention of hip osteoarthritis. “It has been known for a long time that there is a link between body weight and osteoarthritis. Many researchers have tried to find dietary components influencing the condition, but this is the first large scale study of diet in twins. If our results are confirmed by follow-up studies, this will point the way towards dietary intervention or targeted drug therapy for people with osteoarthritis.”

Professor Ian Clark of the University of East Anglia said: “Osteoarthritis is a major health issue and this exciting study shows the potential for diet to influence the course of the disease. With further work to confirm and extend these early findings, this may open up the possibility of using diet or dietary supplements in the future treatment osteoarthritis.”

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Omega-3 foods prevent eye disease

Eating a diet rich in omega-3 fatty acids appears to protect seniors against the onset of a serious eye disease known as age-related macular degeneration (AMD).  Researchers did a fresh analysis of a one-year dietary survey conducted in the early 1990s. The poll involved nearly 2,400 seniors between the ages of 65 and 84 living in Maryland’s Eastern Shore region, where fish and shellfish are eaten routinely.

While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD had consumed less fish and seafood containing omega-3 fatty acids. After their food intake was assessed, participants underwent eye examinations. About 450 had AMD, including 68 who had an advanced stage of the disease, which can lead to severe vision impairment or blindness. Prior evidence suggested that dietary zinc is similarly protective against AMD, so the researchers looked to see if zinc consumption from a diet of oysters and crabs reduced risk of AMD, but no such association was seen.

The researchers believe that the low dietary zinc levels relative to zinc supplements could account for the absence of such a link. However, they cautioned against people to start taking omega-3 supplements to protect against AMD based on this study because they are not sure that the above results have sufficient power to draw any conclusions. The correlation is important but larger studies with longer term follow-up are needed before being able to properly assess the impact.

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Mediterranean diet cuts Alzheimer’s

Alzheimer’s disease, a major form of dementia, has no cure. Luckily, diet and lifestyle can be modified to reduce the risk. For instance, Mediterranean diet and physical activity may each independently reduce the risk of the condition, according to a study in the Aug 2009 issue of Journal of American Medical Association. Dr. N. Scarmeas and colleagues of Taub Institute for Research in Alzheimer’s Disease and the Aging Brain and Department of Neurology at Columbia University Medical Center found men and women those who adhered most closely to Mediterranean diet were 40 percent less likely to be diagnosed with Alzheimer’s disease during a average of 5.4-year follow-up, compared to those who adhered to the diet least closely.

The researchers also found those who most actively engaged in physical activity were up to 33 percent less likely to be diagnosed with Alzheimer’s compared with those who were least active. For the study, Scarneas et al. followed 1880 community-dwelling elderly people who lived without dementia at baseline in New York for their dietary habits and physical activity.

Adherence to a Mediterranean-style diet was assessed on a scale of 0-9, or trichotomized into low, middle, or high and dichotomized into low and high. Physical activity was trichotomized into no physical activity, some, and much and dichotomized into low and high. Neurological and neuropsychological measures were conducted about every 1.5 years from 1992 to 2006. During the 5.4-year follow-up, 282 incident cases of Alzheimer’s were identified.

Those who adhered to the Mediterranean diet with a high score were at 40 percent reduced risk of Alzheimer, compared to those on the diet with a low score. A Mediterranean diet with a middle score did not seem to help compared to a diet with a low score. Those who engaged in some physical activity or much physical activity were at a 25 percent or 33 percent reduced risk of Alzheimer’s disease, respectively, compared with those who did no physical activity. Men and women who had neither followed Mediterranean diet nor much physical activity had an absolute Alzheimer’s risk of 19 percent. This is compared to 12 percent for those who followed both high scored Mediterranean diet and engaged in much physical activity – a difference of 45 percent.

The researchers concluded “both higher Mediterranean-type diet adherence and higher physical activity were independently associated with reduced risk for AD (Alzheimer’s disease).”

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Obesity leads to Vitamin D deficiency

People who weigh more have lower circulating levels of Vitamin D according to recent research conducted at the Rikshospitalet-Radiumhospitalet Medical Center in Oslo, Norway and published in the Journal of Nutrition. Lead researcher, Zoya Lagunova, MD and her colleagues measured the serum levels of Vitamin D and 1,25(OH)2D in 1,779 patients at a Medical and Metabolic Lifestyle Management Clinic in Oslo, Norway. The associations among 1,25(OH)(2)D, serum 25-hydroxyvitamin D [25(OH)D], and body composition were analyzed. Lagunova noted that generally people with higher BMI had lower levels of Vitamin D. Age, season, and gender were also found to influence serum 1,25(OH)(2)D.

Vitamin D is not a true vitamin, but rather a vitamin-steroid thought to play a key role in the prevention of cancer, cardiovascular disease, diabetes, multiple sclerosis and other diseases. It is likely not coincidental that obesity is also a risk factor for many of these diseases. Vitamin D is vital to the regulation of calcium. Studies have shown that calcium deficiency increases the production of synthase, an enzyme that converts calories into fat. It has been shown that calcium deficiency can increase synthase production by up to 500 percent. Vitamin D has also been shown to play a role in the regulation of blood sugar levels; proper blood sugar regulation is vital to the maintenance of a healthy weight. Vitamin D is produced from sunlight and converted into various metabolites. It is stored in fat tissue. According to Lagunova, obese people may take in as much Vitamin D as other people; however, because it is stored in fat it may be less available. This may result in lower circulating levels of Vitamin D.

A previous study conducted by Shalamar Sibley, MD, MPH, an assistant professor of medicine at the University of Minnesota, showed that subjects who have higher levels of Vitamin D at the start of a weight loss diet lose more weight than those with lower levels. The study measured Vitamin D levels of 38 overweight men and women both before and after following an 11-week calorie-restricted diet. Vitamin D levels at the start of diet was an accurate predictor of weight loss…those with higher levels of Vitamin D lost more weight. It was found that for every nanogram increase in Vitamin D precursor, there was an 1/2 pound increase in weight loss.

Seventy-five percent or more of Americans, teenage and older, are Vitamin D deficient according to a recent study published in the Archives of Internal Medicine. According to the Gallup-Healthways Well-Being Index, 26.5% of American are obese. More research needs to be conducted into the exact role Vitamin D plays in obesity and weight loss and the possibility of increased Vitamin D consumption (through the form of supplementation and/or increased sun exposure) being a key factor to achieving a healthy weight.

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Tomatoes Fight Cholesterol

If you want to wage battle against cholesterol and other lipids (fat) that can contribute to vascular disease, then make tomatoes a big part of your diet. Scientists say this popular fruit contains a nutrient that can fight vascular disease such as stroke and arteriosclerosis.

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Tomatoes fight more than cholesterol and fat

Excessive levels of lipids, such as cholesterol and triglycerides in the bloodstream, a condition known as dyslipidemia, can lead to potentially deadly diseases such as arteriosclerosis, cirrhosis, and stroke. Scientists from Kyoto University and New Bio-industry Initiatives, Japan, report that a compound called 9-oxo-octadecadienoic extracted from tomatoes can boost oxidation of fatty acids and contribute to the regulation of lipid metabolism by the liver. These qualities indicate that 9-oxo-octadecadienoic acid can fight cholesterol and other lipids and therefore help prevent vascular diseases.

Vascular disease is a general term used to describe diseases that affect the blood vessels. The Vascular Disease Foundation offers information on nearly two dozen different conditions that fit this category, including abdominal aortic aneurysm, carotid artery disease, deep vein thrombosis, lymphedema, peripheral artery disease, and stroke.

Tomatoes are also valued for other health benefits. Much research has been dedicated to a potent antioxidant in tomatoes, lycopene, and its potential in the fight against various types of cancer, and especially prostate cancer. Tomatoes also contain excellent levels of other nutrients, including niacin, which helps lower cholesterol; and potassium, which reduces blood pressure and the risk of heart disease.

Dr. Teruo Kawada, who is from Kyoto University and who led the study, noted that “Finding a compound which helps the prevention of obesity-related chronic diseases in foodstuffs is a great advantage to tackling these diseases. It means that the tomato allows people to easily manage the onset of dyslipidemia through their daily diet.” To help the fight against cholesterol and other fats that contribute to vascular disease, enjoy more tomatoes.

SOURCES:
Kim YI et al. Molecular Nutrition & Food Research doi:10.1002/mnfr.201000264

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