All Posts tagged effect

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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Can soy stop prostate cancer spread

Prostate cancer is the second most common cause of cancer related deaths in men. Previous cell and animal research suggests that genistein, a potent soy isoflavone, may prevent the spread of prostate cancer. Now research reports that a genistein-derived drug may help prevent the spread of prostate cancer in men with prostate cancer.

The study, presented at the Ninth Annual American Association for Cancer Research Frontiers in Cancer Prevention Research Conference, investigated the effect of the genistein-drug in men with localized prostate cancer. Researchers at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University administered the genistein-drug once daily to 38 men with localized prostate cancer one month before prostate surgery.

The participant’s prostate cancer cells were analyzed after surgery. The researchers found an increased expression of genes that stop cancer cell spread (metastasis). Furthermore, there was a decreased expression of genes that enhance metastasis.

“The first step is to see if the drug has the effect that you want on the cells and the prostate, and the answer is ‘yes, it does,'” says lead researcher Raymond Bergan, MD, professor of hematology and oncology at Northwestern University Feinberg School of Medicine, in a news release. “All therapies designed to stop cancer cell movement that have been tested to date in humans have basically failed have because they have been ineffective or toxic. If this drug can effectively stop prostate cancer from moving in the body, theoretically, a similar therapy could have the same effect on the cells of other cancers.”

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Fish diet lowers risk of stroke

Fish diet lowers risk of stroke

Women who eat more than three servings of fish per week are less likely to experience a stroke, a new study suggests. Specifically, fish-lovers in Sweden were 16 percent less likely to experience a stroke over a 10-year-period, relative to women who ate fish less than once a week. “Fish consumption in many countries, including the U.S., is far too low, and increased fish consumption would likely result in substantial benefits in the population,” said Dr. Dariush Mozaffarian of the Harvard School of Public Health. When choosing fish to eat, it’s best to opt for fish that are rich in omega-3 fatty acids, found most abundantly in fatty fish like salmon, mackerel and albacore tuna. “But any fish is better than none,” Mozaffarian noted.

 

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“Indeed, these fatty acids likely underlie the benefits of fish on stroke risk”, said study author Dr. Susanna Larsson of the Karolinska Institute in Stockholm. “These fatty acids may reduce the risk of stroke by reducing blood pressure and blood (fat) concentrations.”

This is not the first study to suggest that people who eat more fish have a lower risk of stroke, and experts already recommend a fishy diet to reduce the risk of cardiovascular problems, Mozaffarian added. “This study supports current recommendations.” Earlier this year, for instance, a study showed that middle-aged and older men who eat fish every day are less likely than infrequent fish eaters to develop a suite of risk factors for heart disease, diabetes and stroke.

In the current study, published in the American Journal of Clinical Nutrition, Larsson and her colleagues looked at 34,670 women 49 to 83 years old. All were free of cardiovascular disease and cancer at the beginning of the study, in 1997. During 10 years of follow-up, 1,680 of the women (4 percent) had a stroke. Stroke caused by blockage of an artery that supplies blood to the brain — also known as a “cerebral infarction” or “ischemic stroke” — was the most common event, representing 78 percent of all strokes in the study. Other types of strokes were due to bleeding in the brain, or unspecified causes.

Women who ate more than three servings of fish per week had a 16 percent lower risk of stroke than women who ate less than one serving a week. “Not a small effect,” Mozaffarian said, noting that it was roughly equivalent to the effect of statin drugs on stroke risk. Furthermore, the researchers asked women about their diets only once, using a questionnaire, which might have caused errors that would underestimate the link between a fishy diet and stroke risk, he explained. “So, the true risk reduction may be larger.”

Interestingly, women appeared to benefit most from eating lean fish, when other research shows fatty fish is better for health. This finding may stem from the fact that most fatty fish, such as herring and salmon, is eaten salted in Sweden, Larsson explained. “A high intake of salt increases blood pressure and thus may increase the risk of stroke,” she said. “So the protective effects of fatty acids in fatty fish may be attenuated because of the salt.”

Indeed, when it comes to fish, not all have equal benefits, Mozaffarian noted – for instance, he said, research has not shown any cardiovascular benefits from eating fast food fish burgers or fish sticks. In addition, women of childbearing age should avoid certain types of fish known to carry relatively high levels of pollutants, such as shark and swordfish, Mozaffarian cautioned. “This is a very, very short list of fish to avoid or minimize — there are many, many other types of fish to consume,” he said. “Women at risk of stroke are generally beyond their child-bearing years, and so for these women, all types of fish can be consumed.”

Larsson and her team speculate that certain nutrients in fish, such as fatty acids and vitamin D, might explain its apparent benefits. The Swedish study cannot prove cause and effect for high fish consumption and lowered stroke risk, however. For instance, fish consumption could be a sign of a generally healthier lifestyle or some other mechanism at work. Last December, Larsson and colleagues published data from the same group of women in the journal Stroke showing that those who eat a lot of red meat may also be putting themselves at increased risk of stroke.

SOURCE: bit.ly/dKunk8 American Journal of Clinical Nutrition, online December 29, 2010.

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Diabetes Risk from Dining Out

A GOURMET meal may be as bad for you as a Big Mac, according to diabetes researchers who are alarmed at the rise in young men diagnosed with the disease.Corporate lunches and dinners at restaurants dishing up rich, fatty foods, coupled with sedentary working lives are being blamed for the trend. Dr Neale Cohen, of the Baker IDI Heart and Diabetes Institute, said many patients were unaware meals at upmarket restaurants were often as high in fat, salt and sugar as fast food. 

''Eating out is really code for eating badly,'' Dr Cohen said. ''Whether it's a fine French restaurant or McDonald's, it's the type of food that causes the problem.'' He said doctors at the institute are seeing men as young as 40 affected by type 2 diabetes, which is often triggered by obesity and linked to poor diet. ''Many of my patients will eat out three or four times a week for work and we are seeing 40-year-old businessmen who are in real trouble. To have diabetes at that age and otherwise be perfectly well with very little family history, is a really worrying thing.''

Dr Cohen recommends his patients only eat out once a week but said the ''MasterChef effect'' was encouraging people to re-create the elaborate dishes at home.

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Almonds can fight diabetes

Here is another reason to make the tasty almonds a part of your daily diet. The humble tidbit nuts that combine tons of essential nutrients in one delicious package are an effective weapon in fighting type 2 diabetes and cardiovascular diseases, claims a new study. According to researchers, almonds added to the diet have a favorable effect on blood cholesterol levels and insulin sensitivity, two vital risk factors that can trigger diabetes and heart problems.

Lead author of the study, Dr. Michelle Wien, Assistant Research Professor in Nutrition at Loma Linda University’s School of Public Health stated, “We have made great strides in chronic disease research from evidence of effective treatment to evidence of effective prevention. “It is promising for those with risk factors for chronic diseases, such as type 2 diabetes and cardiovascular disease, that dietary changes may help to improve factors that play a potential role in the disease development.”

In a bid to assess the impact of almond enriched diet as a prescription for physical wellness, the researchers conducted a study. The focus of the study was to analyze the effect of the humble nut on the progression of type 2 diabetes and cardiovascular disease. The investigators enrolled a group of 65 adults comprising 48 women and 17 men with pre-diabetes in their mid-50s. The study subjects were split into two groups. As a part of the study, one group was assigned to almonds while the second formed the control group. The control group followed a diet recommended by the American Diabetes Association (ADA).The group assigned to almonds conformed to a similar diet but also added 20 percent calories from almonds. All the participants were asked to consume the same amount of calories from carbohydrate-containing foods, such as pasta, bread, and rice. However, those consuming the almond-enriched diet reported a lower intake of carbohydrate-containing food items.

After a period of 16 weeks, the investigators compared the insulin and cholesterol levels of both the groups. It was noticed that people consuming almond-enriched diet exhibited marked improvement in their insulin sensitivity and a dramatic reduction in LDL cholesterol as opposed to those eating the nut-free regular diet.

The study was conducted at the University of Medicine and Dentistry of New Jersey. The findings of the research are published in the ‘Journal of the American College of Nutrition

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Chocolate reduces effect of Chronic Fatigue Syndrome

Chocolate reduces effect of Chronic Fatigue Syndrome

Researchers from the University of Hull and the Hull York Medical School have found dark chocolate has a significant effect on reducing the symptoms of Chronic Fatigue Syndrome (CFS). The research, published in Nutrition Journal, found that polyphenol rich chocolate eases the condition, with subjects noting significant improvements to their well-being. Chocolate is known to increase neurotransmitters like phenyl ethylamine, serotonin, and anandamide in the brain, but this is the first time that polyphenol rich chocolate in people with CFS has been studied.

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Above: Professor Steve Atkin.

Subjects with CFS having severe fatigue of at least 10 out of 11 on Chalder Fatigue Scale were enrolled on the pilot study. Participants were given one of two types of chocolate, one with a high cocoa content and the other without.

Over an eight week period the volunteers consumed one type of chocolate followed by a two week wash out period and then another eight weeks of eating the other variety. The dark chocolate contained 85% cocoa solids with the alternative containing none. Each individual bar weighed 15g with each volunteer expected to eat three per day, and also told not to consume more or make changes to their diet.

Researchers also noted the weight of subject did not significantly alter despite consuming an extra 245 calories per day for two months.

Professor Steve Atkin who led the study says: “The significance of the results is particularly surprising because of the small number of subjects in the study. A further study is needed to see what the effects would be on a larger group of people, but this is potentially very encouraging news for those who suffer from Chronic Fatigue Syndrome.”

This latest finding follows recent research also carried out at the University of Hull and the Hull York Medical School where dark chocolate was found to help reduce the risk of heart attacks in people with Type 2 diabetes by increasing the amount of good cholesterol in the blood stream.

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Low Vitamin D levels common in breast cancer

More than half of women with breast cancer have low vitamin D levels, British researchers report.”Women with breast cancer should be tested for vitamin D levels and offered supplements, if necessary,” says researcher Sonia Li, MD, of the Mount Vernon Cancer Centre in Middlesex, England. The findings were presented at the San Antonio Breast Cancer Symposium.

Some studies have suggested a link between low vitamin levels and breast cancer risk and progression, but others have not, she says. No studies have proven cause and effect. Previous research suggests a biologic rationale for vitamin D putting the brakes on breast cancer development and spread, Li says. Breast cancer cells have vitamin D receptors, and when these receptors are activated by vitamin D, it triggers a series of molecular changes that can slow cell growth and cause cells to die, she says. Even if it does not have a direct effect on the tumor, vitamin D is needed to maintain the bone health of women with breast cancer, Li says. That's especially important given the increasing use of aromatase inhibitors, which carry an increased risk of bone fractures, she says.

Vitamin D is found in some foods, especially milk and fortified cereals, and is made by the body after exposure to sunlight. It is necessary for bone health.

For the study, Li and colleagues collected blood samples from 166 women with breast cancer and measured their levels of vitamin D. Of the total, 46% had vitamin D insufficiency, defined as levels between 12.5 and 50 nanomoles per liter (nmol/L) of blood. Another 6% had vitamin D deficiency, with levels lower than 12.5 nmol/L. When ethnicity was considered, vitamin D levels were lower in Asian women than in white or other women: an average of about 36 nmol/L vs. 61 nmol/L and 39 nmol/L, respectively.

The researchers theorized that vitamin D levels would be higher in the summer, when there are more daylight hours, but the study showed no association between vitamin D levels and seasons. Last month, the U.S. Institute of Medicine issued updated guidelines stating that a blood level of 50 nmol/L (or 20 nanograms/milliliter) is sufficient for 97% of people.

This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.

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Evolution and Type I Diabetes

The idea that disease-causing genes can be beneficial is not new. The most clear-cut case involves a gene variant that, when present in two copies, causes sickle cell anaemia, which can result in severe pain, organ damage and death. Although it seems that natural selection would work to eliminate the disorder, the variant remains prevalent in some areas of Africa because people with just a single copy are less susceptible to malaria. Evolutionarily the trade-off is worth it: Far more people are protected from malaria than ever develop sickle cell anaemia even in today’s environment.

Unlike sickle cell anaemia, which is caused by a mutation in just one gene, many complex diseases are associated with several variants – specific locations in the DNA where the nucleotide ‘letters’ vary between individuals. These locations are known as SNPs, for single nucleotide polymorphisms. Some of these SNPs are associated with an increased disease risk, while others protect against developing the disease. When calculating an individual’s overall genetic risk, it’s necessary to consider the net effect of all of his or her variants.

Researchers at Stanford University picked seven well-known conditions to study: type-1 and type-2 diabetes, rheumatoid arthritis, hypertension, Crohn’s disease, coronary artery disease and bipolar disorder. Previous genome wide association studies have identified several hundred SNPs associated with each disorder. Corona found that of the top SNPs associated with type-1 diabetes, 80 have been recently increasing in prevalence, meaning that they underwent positive selection. Of these, a surprising 58 are associated with an increased risk of the disorder, while 22 appear protective. Similarly, SNPs associated with an increased risk for rheumatoid arthritis were found to be positively selected. In contrast to type-1 diabetes and rheumatoid arthritis, Corona found that we’re evolving away from a tendency to develop Crohn’s disease (that is, more protective SNPs than risky SNPs have been positively selected).

Results for the other three disorders – type-2 diabetes, coronary artery disease and bipolar disorder – showed that protective and risky SNPs were positively selected in about equal proportions. ‘Now we’re starting to see little hints as to why this might be the case,’ said Butte. For example, a recent study in another lab showed that genetic variations in an antiviral response gene called IFIH1 that improve its ability to protect against enterovirus infection (and the resulting severe, potentially deadly, abdominal distress) also increase a carrier’s risk for type-1 diabetes. And scientists who study global disease patterns have long noted that the prevalence of tuberculosis varies inversely with that of rheumatoid arthritis.

‘It’s possible that, in areas of the world where associated triggers for some of these complex conditions are lacking, carriers would experience only the protective effect against some types of infectious disease,’ said Butte, who pointed out that the cumulative effect of many SNPs in a person’s genome may buffer the effect of any one variant, even if it did raise a person’s risk for a particular condition.

Regardless of the reason, some evolutionary tenets still apply. Healthier people are, presumably, more likely to reproduce and pass those same genes – be they protective or risky – to their offspring. When conditions changed because of differences in diet, exposures or location as populations move around the globe, carriers of the risky SNPs began to develop the conditions we struggle with today.

Corona and Butte are now expanding their investigation to include even more SNPs and diseases. They are also looking at the genetic profile of various types of tumours to see if there’s evidence for positive evolutionary pressure there as well.

‘Even though we’ve been finding more and more genetic contributions to disease risk,’ said Butte, ‘that’s not really an appealing answer. There have got to be some other reasons why we have these conditions.’

Source: Stanford University Medical Centre

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Fish oil enhances effect of Green Tea on Alzheimers

Fish oil, when combined with epigallocatechin‑3‑gallate (EGCG—a polyphenol and antioxidant found in green tea), may affect chemical processes in the brain associated with Alzheimer's disease, according to a study published in Neuroscience Letters. This study, which used an animal (mouse) model of Alzheimer's disease, builds on previous research linking the disease to peptides (amino acid chains) called beta‑amyloids and laboratory studies suggesting that EGCG decreases memory problems and beta‑amyloid deposits in mice.

Researchers from the University of South Florida divided Alzheimer's disease‑model mice into five feeding groups. During a period of 6 months, each group was fed one of five diets: fish oil only; high‑dose EGCG; low‑dose EGCG; low‑dose EGCG and fish oil; or a regular diet (control). The researchers observed that low‑dose EGCG alone did not reduce the Alzheimer's disease-related chemical processes in the brain. However, the mice fed the combination of fish oil and EGCG had a significant reduction in amyloid deposits that have been linked with Alzheimer's disease.

Upon examination of blood and brain tissues of the mice, the researchers found high levels of EGCG in the mice that were fed the combination of fish oil and low‑dose EGCG compared with those fed low‑dose EGCG alone. A possible explanation, according to the researchers, is that fish oil enhances the bioavailability of EGCG—that is, the degree to which EGCG was absorbed into the body and made available to the brain. This effect, in turn, may contribute to the increased effectiveness of this combination. Further research is necessary, however, to determine if the combination of fish oil and EGCG affects memory or cognition, and whether it might have potential as an option for people at risk of developing Alzheimer's disease.

Reference

Giunta B, Hou H, Zhu Y, et al. Fish oil enhances anti‑amyloidogenic properties of green tea EGCG in Tg2576 mice. Neuroscience Letters. 2010;471(3):134–138.

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12 Genetic Risk Factors for Diabetes

“Once we know the exact causes of type 2 diabetes, we can develop more effective prevention and therapy strategies,” said Dr. Thomas Illig, research group leader at the Institute of Epidemiology of Helmholtz Zentrum München and one of the corresponding authors of the study. Dr. Cornelia Huth, who played a key role in the selection of the study participants and the analyses of Helmholtz Zentrum München, added: “What enabled us to identify these factors with a high level of confidence is the large number of investigated subjects in this collaborative study. Each factor by itself contributes only slightly to the entire diabetes risk. But to find out more about the pathogenic mechanisms of the disease, even these slight contributions are important.” Dr. Christian Herder and Dr. Wolfgang Rathmann, both of whom are research group leaders at the German Diabetes Center, pointed out: “One important finding of the new study is that some of the gene loci associated with increased type 2 diabetes risk are also risk variants for other diseases such as coronary heart disease, autoimmune diseases and cancer. This suggests that specific proteins could be relevant for several diseases at the same time.”

Type 2 diabetes is a disorder of glucose homeostasis. Characteristic features of this disorder are that the effect and sufficient production of the hormone insulin become lost. The pathogenic mechanisms of this disease are not yet fully understood. It is known, however, that the combination of genetic susceptibility and lifestyle factors leads to diabetes. In Germany alone, not less than seven percent of the population has been diagnosed with the disease – altogether almost six million people. Additionally, studies show that several million men and women in Germany suffer from as yet undiagnosed and thus untreated diabetes.

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