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Category: nutrition

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Can you have too high levels of vitamin D? The researchers themselves say that the results show there is a J shaped curve linking vitamin D levels in the blood and mortality - both too high and too low levels are linked to higher levels of mortality. From Science Daily:

High levels of vitamin D is suspected of increasing mortality rates

The level of vitamin D in our blood should neither be too high nor to low. Scientists have now shown that there is a connection between high levels of vitamin D and cardiovascular deaths.

In terms of public health, a lack of vitamin D has long been a focal point. Several studies have shown that too low levels can prove detrimental to our health. However, new research from the University of Copenhagen reveals, for the first time, that also too high levels of vitamin D in our blood is connected to an increased risk of dying from a stroke or a coronary.

"We have studied the level of vitamin D in 247,574 Danes, and so far, it constitutes the world's largest basis for this type of study. We have also analysed their mortality rate over a seven-year period after taking the initial blood sample, and in that time 16,645 patients had died. Furthermore, we have looked at the connection between their deaths and their levels of vitamin D," Professor at the Department of Clinical Medicine, Peter Schwarz explains.

The conclusion is clear: the study confirms that there is indeed a correlation between mortality rates and too low levels of vitamin D, but the new thing is that the level of vitamin D can also be too high.

"If your vitamin D level is below 50 or over 100 nanomol per litre, there is an greater connection to deaths. We have looked at what caused the death of patients, and when numbers are above 100, it appears that there is an increased risk of dying from a stroke or a coronary. In other words, levels of vitamin D should not be too low, but neither should they be too high. Levels should be somewhere in between 50 and 100 nanomol per litre, and our study indicates that 70 is the most preferable level," Peter Schwartz states.

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This interesting study raises the possibility that eating certain foods or probiotics  (beneficial bacteria) may prevent diabetes. Note that Akkermansia is a bacteria with one species Akkermansia muciniphila . In Wikipedia:"Researchers have discovered that Akkermansia muciniphila may be able to be used to combat obesity and type 2 diabetes...The bacterium is naturally present in the human digestive tract at 3-5%, but has been seen to fall with obesity." Regarding Prevotella, in Wikipedia: "Studies also indicate that long-term diet is strongly associated with the gut microbiome composition—those who eat plenty of protein and animal fats typical of Western diet have predominantly Bacteroides bacteria, while for those who consume more carbohydrates, especially fiber, the Prevotella species dominate." From Science Daily:

Gut bacteria may contribute to diabetes in black males

African American men at elevated risk for developing type 2 diabetes may have fewer beneficial and more harmful intestinal bacteria, according to new research.

"The 'signature' of the gut microbiota -- the relative abundance of various bacteria and other microbes in the digestive system -- could be another useful tool in assessing a person's risk for developing diabetes," said Ciubotaru. Ciubotaru and her colleagues, including principal investigator Dr. Elena Barengolts,... found that a specific microbiota is associated with stable, normal blood glucose levels, while a different profile is associated with glucose levels that indicate pre-diabetes.

"The study provides additional reasons for physicians to recommend foods, such as prebiotics, which improve the growth and activity of helpful gut bacteria," said Barengolts. The gut microbiota helps digest food; fights infections; and plays an important role in keeping the immune system healthy. It is greatly influenced by genetics, diet and other environmental factors. Previous research has implicated an unhealthy or unbalanced microbiota as a contributing factor to metabolic disorders, including obesity and diabetes. The species that make up an individual's gut microbiota, as well as their abundance, can be identified by stool sample analysis.

The researchers determined the gut microbiotas of 116 African-American male veterans, age 45 to 75, participating in the D Vitamin Intervention in VA, or DIVA study. The aim of the DIVA study, which has 173 total participants and is funded by the Department of Veterans Affairs, is to determine if vitamin D supplementation can prevent diabetes in men with risk factors for developing the disease.

Participants were divided into four groups based on changes in their blood sugar levels as determined at the start and end of the one-year study. The groups included men whose glucose levels remained normal (non-pre-diabetic); those with stable levels indicative of pre-diabetes; those whose levels indicated a worsening of glucose control; and those whose levels improved. All the men provided stool samples for analysis of their gut microbiota.

Men whose blood sugar levels stayed normal over the year had more gut bacteria that are considered beneficial for metabolic health, whereas those who stayed pre-diabetic had fewer beneficial bacteria and more harmful bacteria. In addition, the group whose levels improved had more abundant Akkermansia--healthy bacteria--than the group that maintained normal blood sugar control throughout the year.

The study suggests that differences in the gut microbiota already exist in pre-diabetes, Barengolts said. Although the study found connections between composition of the gut microbiota and blood sugar control, Barengolts said further research is needed to confirm these findings and evaluate whether certain intestinal bacteria cause type 2 diabetes. However, based on other research her group has conducted and studies in animals, she speculated that the foods we eat affect our diabetes risk through our gut microbiota. If the mix of organisms in the intestinal tract is indeed responsible for the development of type 2 diabetes, she said, it may be possible to lower one's risk by changing the gut bacteria.

More details about that same study. From Medpage Today:

Prediabetes Patients Have Fewer Gut Bugs

They were put into one of four groups: those with a stable glucose tolerance, those with stable impaired fasting glucose or stable impaired glucose tolerance, those with worsened glucose tolerance, and those with improved glucose tolerance. There were significant differences in bacterial composition between the first and second groups (P=0.03) at the phylum level. Bacteroidetes was higher and Firmicutes was lower with worse glycemic control in the second group. 

Proteobacteria decreased over the period in groups 2 and 4 compared with group 1 (P=0.04 for both). At the family and genus levels, in group 2 versus group 1 there was less Prevotella, and a higher Bacteroides/Prevotella ratio in the second group at 5.6 to 2.7 (P=0.05). There was also less Enterobacteriaceae (P=0.03), and more Ruminococcae (P=0.01) and Veillonellaceae (P=0.02).

"We speculate that lower abundance of Prevotella may be associated with worsening glycemia, and, conversely, higher abundance of Akkermansia might be associated with improving glycemia, thus corroborating suggestions from previous studies," the researchers said.

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What was really interesting in the recent study findings was not just that vegetarian diets are associated with an overall lower incidence of colorectal cancers, but that pescovegetarians (eat fish) had the lowest risk of all compared to nonvegetarians. That is really strong support for eating fish. From Science Daily:

Vegetarian diet linked to lower risk of colorectal cancers

Eating a vegetarian diet was associated with a lower risk of colorectal cancers compared with nonvegetarians in a study of Seventh-Day Adventist men and women, according to an article published online by JAMA Internal Medicine.

Colorectal cancer is the second leading cause of cancer death in the United States. Although great attention has been paid to screening, primary prevention through lowering risk factors remains an important objective. Dietary factors have been identified as a modifiable risk factor for colorectal cancer, including red meat which is linked to increased risk and food rich in dietary fiber which is linked to reduced risk, according to the study background.

Among 77,659 study participants, Michael J. Orlich, M.D., Ph.D., of Loma Linda University, California, and coauthors identified 380 cases of colon cancer and 110 cases of rectal cancer. Compared with nonvegetarians, vegetarians had a 22 percent lower risk for all colorectal cancers, 19 percent lower risk for colon cancer and 29 percent lower risk for rectal cancer. Compared with nonvegetarians, vegans had a 16 percent lower risk of colorectal cancer, 18 percent less for lacto-ovo (eat milk and eggs) vegetarians, 43 percent less in pescovegetarians (eat fish) and 8 percent less in semivegetarians, according to study results.

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A big study that found that eating a greater proportion of plant-based foods (fruits, vegetables, grains, beans, potatoes, nuts, olive oil), as compared to animal-based foods, is linked to lower risks of dying from heart disease and stroke.

From Science Daily: Semi-veggie diet effectively lowers heart disease, stroke risk.

A pro-vegetarian diet -- one that has a higher proportion of plant-based foods compared to animal-based foods is linked to lower risks of dying from heart disease and stroke, according to new research presented at the American Heart Association EPI/Lifestyle 2015 meeting. In an observational study, researchers analyzed the eating and lifestyle habits of 451,256 Europeans.

People who ate the most pro-vegetarian style diets (up to 70 percent of food coming from plant sources) had a 20 percent lower risk of dying from cardiovascular disease, compared to those who were the least pro-vegetarian (<45 percent). "A pro-vegetarian diet doesn't make absolute recommendations about specific nutrients. It focuses on increasing the proportion of plant based foods relative to animal-based foods, which results in an improved nutritionally balance diet," said Camille Lassale, Ph.D., lead author and an epidemiologist at Imperial College London's School of Public Health.

Participants were part of the European Prospective Investigation into Cancer and Nutrition (EPIC) study, started in 1992. The study included nearly half a million people from 10 countries who were free of chronic diseases at the start of the study, 35 to 70 years and followed for 12 years on average....Researchers scored participants based on the types of foods they ate. Points were given for eating foods from seven plant food groups: vegetables, fruit, beans, cereals, potatoes, nuts, and olive oil. Points were subtracted for five animal food groups: meats, animal fats, eggs, fish, and other seafood or dairy products. Based on their scores, participants were categorized from the least pro-vegetarian to the most. 

Researchers analyzed the relationship between eating habits and death risks from heart disease and stroke."Instead of drastic avoidance of animal-based foods, substituting some of the meat in your diet with plant-based sources may be a very simple, useful way to lower cardiovascular mortality," said Lassale. These findings are in line with the wealth of evidence on benefits of eating plant foods to prevent CVD.

The American Heart Association recommends following a heart-healthy diet, which could also be described as a pro-vegetarian diet. It is high in fruits, vegetables, whole grains, legumes, beans, and nuts, low-fat dairy, beans, skinless poultry, and fish. It encourages eating foods low in saturated and trans fats and sodium, and limiting added sugars and red meats.

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Gut bacteria in children varies among different Asian countries. A recent study found that microbiota of 303 subjects could be classified into two main clusters: driven by Prevotella (P-type) or by Bifidobacterium/Bacteroides (BB-type).

The majority of children in China, Japan and Taiwan harbored Bifidobacterium/Bacteroides (BB type), whereas those from Indonesia and Khon Kaen in Thailand mainly harbored Prevotella (P-type). It was interesting in that even eating different types of rice result in different gut bacteria.

From Asian Scientist: Diet, Location And Your Kid’s Gut Bacteria

An Asia-wide study of the gut microbiota of primary school children has identified differences linked to diet and geographical location.  ...continue reading "Gut Bacteria of School Children In Different Asian Countries"

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A large study found that eating nuts or peanuts several times a week is associated with lower death rates, especially from cardiovascular disease. Note that a serving is a small handful or 1.5 ounces of whole nuts or 2 tablespoons of nut butter.

From Science Daily: Peanut consumption associated with decreased total mortality and mortality from cardiovascular diseases

If you're looking for a simple way to lower your risk of dying from a heart attack, consider going nuts. Researchers at Vanderbilt University and the Shanghai Cancer Institute examined the association of peanut and nut consumption with mortality among low-income and racially diverse populations and found that intake of peanuts was associated with fewer deaths, especially from heart disease.

"Nuts are rich in nutrients, such as unsaturated fatty acids, fiber, vitamins, phenolic antioxidants, arginine and other phytochemicals. All of them are known to be beneficial to cardiovascular health, probably through their anti-oxidative, anti-inflammatory and endothelial function maintenance properties," Shu said.

While research has previously linked nut consumption with lower mortality, those studies focused mainly on higher-income, white populations. This study was the first to discover that all races -- blacks, whites and Asians alike -- could potentially increase heart health by eating nuts and peanuts.

This study was based on three large ongoing cohort studies. Participants included more than 70,000 Americans of African and European descent from the Southern Community Cohort Study (SCCS), who were mostly low-income, and more than 130,000 Chinese from the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS).... In total, more than 14,000 deaths were identified, with a median follow-up of 5.4 years in the SCCS, 6.5 years in the SMHS, and 12.2 years in the SWHS.

Peanut consumption was associated with decreased total mortality, particularly cardiovascular mortality (i.e., 17-21 percent reduction in total mortality, and 23-38 percent reduction in cardiovascular mortality for the highest quartile intake group compared to the lowest quartile group) across all three racial/ethnic groups, among both men and women, and among individuals from low-SES groups.

The American Heart Association recommends eating four servings of unsalted, unoiled nuts a week. However, nutrient-rich nuts are also high in calories, so don't eat too many if you're watching your weight. A serving size is a small handful or 1.5 ounces of whole nuts or 2 tablespoons of nut butter.

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More research linking moderate coffee consumption with a health benefit. From Medical Daily:

Moderate coffee consumption lessens risk of clogged arteries and heart attacks

People who drink a moderate amount of coffee daily are less likely to develop clogged arteries that could lead to heart attacks, reveals research published online in Heart. Researchers from South Korea found that people consuming three to five cups a day had the least risk of coronary calcium in their arteries.

There has been much debate over the effect of coffee consumption on cardiovascular health.Despite earlier concerns about a potential increase in heart disease risk associated with drinking coffee, a recent meta-analysis of 36 studies showed that moderate coffee consumption was associated with a decreased risk of heart disease. Coffee consumption has been associated with improved insulin sensitivity and reduced risk of type 2 diabetes, but it has also been linked to increased cholesterol concentrations and heightened blood pressure.

An international team of researchers led by the Kangbuk Samsung Hospital, Seoul, in the Republic of Korea, set out to examine the association between coffee consumption and the presence of coronary artery calcium (CAC) which is a early indicator of coronary atherosclerosis - a potentially serious condition where arteries become clogged up by fatty substances known as plaques or atheroma and which can cause the arteries to harden and narrow, leading to blood clots which can trigger a heart attack or a stroke.

They studied a group of 25,138 men and women - average age of 41 - who had no signs of heart disease, attending a health screening examination...They categorised coffee consumption as none, less than one cup a day, one to three cups a day, three to five per day and at least five or more per day. The researchers found the prevalence of detectable CAC was 13.4% amongst the whole group of people and the average consumption of coffee was 1.8 cups per day.

The calcium ratios were 0.77 for people who had less than one cup per day, 0.66 for those having one to three cups every day, 0.59 for those consuming three to five cups per day, and 0.81 for people having at least five cups or more every day compared with non coffee drinkers. The association was similar in subgroups defined by age, sex, smoking status, alcohol consumption, and status of obesity, diabetes, hypertension, and hypercholesterolaemia. The association, therefore, was U-shaped, with participants drinking three to five cups per day having the lowest prevalence of arteries that had clogged up.

Possible explanations for the findings, said the researchers, were that chronic coffee consumption had a possible link to reduced risk of type 2 diabetes, a strong risk factor for atherosclerosis, and that coffee drinking might improve insulin sensitivity and β-cell function.The authors concluded: "Our study adds to a growing body of evidence suggesting that coffee consumption might be inversely associated with CVD [cardiovascular disease] risk.

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Here is an article to what I referred to in my recent Feb. 27 Feast and Famine Diet post about intermittent fasting being beneficial to health and resulting in weight loss. This definitely seems easier than sticking to very low calorie diets weeks on end. From NPR:

Minifasting: How Occasionally Skipping Meals May Boost Health

If you've ever gone to sleep hungry and then dreamed of chocolate croissants, the idea of fasting may seem completely unappealing. But what if the payoff for a 16-hour fast — which might involve skipping dinner, save a bowl of broth — is a boost in energy and a decreased appetite?

This is what we've experienced as we've tried out the so-called 5:2 diet. It's an intermittent fasting approach that, as we've reported, has been popularized by books by British physician and television broadcaster Michael Mosley. The diet calls for two days per week of minifasting where the aim is to go a long stretch, say 14 to 18 hours, without eating. During these two fasting days, you also eat only about 600 calories, give or take. But here's the easy part: The other five days of the week you forget about dieting and return to your normal pattern of eating.

The fascination is what researchers say may be the broader benefits. Scientists are looking into how fasting may help control blood sugar, improve memory and energy and perhaps boost immunity. A study by researchers at the University of Manchester found that when overweight women followed a 5:2 approach, they lost more weight and body fat and improved their insulin resistance compared with women who followed a more traditional diet of limiting calories seven days per week.

One explanation for the success of the 5-2 dieters could be that a day of minifasting can lead to a diminished appetite. As Allison reports on All Things Considered, she found that she's just less hungry the day after a fast.

Mark Mattson, a researcher at the National Institute of Aging, says when we go without food, the body uses up its stored glucose, the basic fuel for the body, and starts burning fat....During fasting, he says, fat can convert to compounds called ketones, "which have beneficial effects in making neurons more resistant to injury and disease." 

There may be an evolutionary explanation for this because humans (and other animals) have fasted intermittently for much of our time on Earth, after all. As a recent paper in the Proceedings of the National Academy of Sciences notes, "The most common eating pattern in modern societies, three meals plus snacks every day, is abnormal from an evolutionary perspective."

Longo and other experts gave Eliza some of their other tips on how to do it right: - Fasting is easier with a buddy. - On a minifast, choose the food you do eat carefully. Researchers recommend high-protein, high-fiber foods. Avoid refined carbs and sugar, which will spike blood sugar and may leave you hungry late in the day. - To minimize temptation, stay out of the kitchen and away from food establishments. - Try a pattern of weekly intermittent fasting for at least a month. Studies have shown that a long-term lifestyle change (and the benefits associated with it) is more likely for people who can stick with the diet for at least a month. And tolerating some hunger gets easier the longer you do it. - Don't be surprised if there are some side effects, like trouble sleeping or gastrointestinal issues.

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Of course some foods are addictive. Anyone who tries to eat just one french fry or one piece of chocolate or one potato chip knows that it's very, very hard to do that. Do people have raw carrot cravings? Nah... Chocolate cravings? Yup..Does this research really tell us anything new? From Science Daily:

Want pizza, chocolate, French fries? Highly processed foods linked to addictive eating

A new University of Michigan study confirms what has long been suspected: highly processed foods like chocolate, pizza and French fries are among the most addictive.

This is one of the first studies to examine specifically which foods may be implicated in "food addiction," which has become of growing interest to scientists and consumers in light of the obesity epidemic.Previous studies in animals conclude that highly processed foods, or foods with added fat or refined carbohydrates (like white flour and sugar), may be capable of triggering addictive-like eating behavior. Clinical studies in humans have observed that some individuals meet the criteria for substance dependence when the substance is food.

Unprocessed foods, with no added fat or refined carbohydrates like brown rice and salmon, were not associated with addictive-like eating behavior.

Individuals with symptoms of food addiction or with higher body mass indexes reported greater problems with highly processed foods, suggesting some may be particularly sensitive to the possible "rewarding" properties of these foods, said Erica Schulte, a U-M psychology doctoral student and the study's lead author...."This is a first step towards identifying specific foods, and properties of foods, which can trigger this addictive response," she said. "This could help change the way we approach obesity treatment. It may not be a simple matter of 'cutting back' on certain foods, but rather, adopting methods used to curtail smoking, drinking and drug use.

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A variation of this study - intermittent fasting (one day eat normally, then have a low-calorie day, repeat) has shown to result in health benefits and weight loss. But both versions show that having some low calorie days are beneficial to health. And once again, antioxidants do not have any health benefits. From Science Daily:

Feast-and-famine diet could help extend life, study suggests

University of Florida Health researchers have found that putting people on a feast-or-famine diet may mimic some of the benefits of fasting, and that adding antioxidant supplements may counteract those benefits.

Fasting has been shown in mice to extend lifespan and to improve age-related diseases. But fasting every day, which could entail skipping meals or simply reducing overall caloric intake, can be hard to maintain..."We started thinking about the concept of intermittent fasting.”

Michael Guo, a UF M.D.-Ph.D. student who is pursuing the Ph.D. portion of the program in genetics at Harvard Medical School, said the group measured the participants’ changes in weight, blood pressure, heart rate, glucose levels, cholesterol, markers of inflammation and genes involved in protective cell responses over 10 weeks.“We found that intermittent fasting caused a slight increase to SIRT 3, a well-known gene that promotes longevity and is involved in protective cell responses,” Guo said.

The SIRT3 gene encodes a protein also called SIRT3. The protein SIRT3 belongs to a class of proteins called sirtuins. Sirtuins, if increased in mice, can extend their lifespans, Guo said. Researchers think proteins such as SIRT3 are activated by oxidative stress, which is triggered when there are more free radicals produced in the body than the body can neutralize with antioxidants. However, small levels of free radicals can be beneficial: When the body undergoes stress -- which happens during fasting -- small levels of oxidative stress can trigger protective pathways, Guo said. “The hypothesis is that if the body is intermittently exposed to low levels of oxidative stress, it can build a better response to it,” Wegman said.

The researchers found that the intermittent fasting decreased insulin levels in the participants, which means the diet could have an anti-diabetic effect as well.

The group recruited 24 study participants in the double-blinded, randomized clinical trial. During a three-week period, the participants alternated one day of eating 25 percent of their daily caloric intake with one day of eating 175 percent of their daily caloric intake. For the average man’s diet, a male participant would have eaten 650 calories on the fasting days and 4,550 calories on the feasting days. To test antioxidant supplements, the participants repeated the diet but also included vitamin C and vitamin E.

At the end of the three weeks, the researchers tested the same health parameters. They found that the beneficial sirtuin proteins such as SIRT 3 and another, SIRT1, tended to increase as a result of the diet. However, when antioxidants were supplemented on top of the diet, some of these increases disappeared. This is in line with some research that indicates flooding the system with supplemental antioxidants may counteract the effects of fasting or exercise, said Christiaan Leeuwenburgh, Ph.D., co-author of the paper and chief of the division of biology of aging in the department of aging and geriatric research.“You need some pain, some inflammation, some oxidative stress for some regeneration or repair,” Leeuwenburgh said. 

On the study participants’ fasting days, they ate foods such as roast beef and gravy, mashed potatoes, Oreo cookies and orange sherbet -- but they ate only one meal. On the feasting days, the participants ate bagels with cream cheese, oatmeal sweetened with honey and raisins, turkey sandwiches, apple sauce, spaghetti with chicken, yogurt and soda -- and lemon pound cake, Snickers bars and vanilla ice cream.