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Category: nutrition

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More long-standing medical advice goes out the window. New advice: avoid diet soda and artificial sweeteners. The amazing part is that our gut bacteria are involved.

From Science Daily: Certain gut bacteria may induce metabolic changes following exposure to artificial sweeteners

Artificial sweeteners -- promoted as aids to weight loss and diabetes prevention -- could actually hasten the development of glucose intolerance and metabolic disease, and they do so in a surprising way: by changing the composition and function of the gut microbiota -- the substantial population of bacteria residing in our intestines. These findings, the results of experiments in mice and humans, ...says that the widespread use of artificial sweeteners in drinks and food, among other things, may be contributing to the obesity and diabetes epidemic that is sweeping much of the world.

For years, researchers have been puzzling over the fact that non-caloric artificial sweeteners do not seem to assist in weight loss, with some studies suggesting that they may even have an opposite effect.

Next, the researchers investigated a hypothesis that the gut microbiota are involved in this phenomenon. They thought the bacteria might do this by reacting to new substances like artificial sweeteners, which the body itself may not recognize as "food." Indeed, artificial sweeteners are not absorbed in the gastrointestinal tract, but in passing through they encounter trillions of the bacteria in the gut microbiota.

The researchers treated mice with antibiotics to eradicate many of their gut bacteria; this resulted in a full reversal of the artificial sweeteners' effects on glucose metabolism. Next, they transferred the microbiota from mice that consumed artificial sweeteners to "germ-free," or sterile, mice -- resulting in a complete transmission of the glucose intolerance into the recipient mice. This, in itself, was conclusive proof that changes to the gut bacteria are directly responsible for the harmful effects to their host's metabolism.... A detailed characterization of the microbiota in these mice revealed profound changes to their bacterial populations, including new microbial functions that are known to infer a propensity to obesity, diabetes, and complications of these problems in both mice and humans.

Does the human microbiome function in the same way? Dr. Elinav and Prof. Segal had a means to test this as well. As a first step, they looked at data collected from their Personalized Nutrition Project (www.personalnutrition.org), the largest human trial to date to look at the connection between nutrition and microbiota. Here, they uncovered a significant association between self-reported consumption of artificial sweeteners, personal configurations of gut bacteria, and the propensity for glucose intolerance. They next conducted a controlled experiment, asking a group of volunteers who did not generally eat or drink artificially sweetened foods to consume them for a week, and then undergo tests of their glucose levels and gut microbiota compositions.

The findings showed that many -- but not all -- of the volunteers had begun to develop glucose intolerance after just one week of artificial sweetener consumption. The composition of their gut microbiota explained the difference: the researchers discovered two different populations of human gut bacteria -- one that induced glucose intolerance when exposed to the sweeteners, and one that had no effect either way. Dr. Elinav believes that certain bacteria in the guts of those who developed glucose intolerance reacted to the chemical sweeteners by secreting substances that then provoked an inflammatory response similar to sugar overdose, promoting changes in the body's ability to utilize sugar.

This image depicts gut microbiota. Credit: Weizmann Institute of Science

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Another study finding health benefits from eating dairy foods (vs not eating any dairy foods).

From Science Daily: A heart-felt need for dairy food: Small serving beneficial, large not necessary

A daily small serve of dairy food may reduce the risk of heart disease or stroke, even in communities where such foods have not traditionally formed part of the diet according to new research.

A study of nearly 4000 Taiwanese, led by Emeritus Professor Mark Wahlqvist from Monash University's Department of Epidemiology and Preventive Medicine and the Monash Asia Institute, considered the role increased consumption of dairy foods had played in the country's gains in health and longevity.

"We observed that increased dairy consumption meant lower risks of mortality from cardiovascular disease, especially stroke, but found no significant association with the risk of cancer," Professor Wahlqvist said.

Milk and other dairy foods are recognised as providing a broad spectrum of nutrients essential for human health. According to the study findings, people only need to eat small amounts to gain the benefits.

"Those who ate no dairy had higher blood pressure, higher body mass index and greater body fatness generally than other groups. But Taiwanese who included dairy food in their diet only three to seven times a week were more likely to survive than those who ate none."

For optimal results, the key is daily consumption of dairy foods -- but at the rate of about five servings over a week. One serving is the equivalent to eight grams of protein: a cup of milk, or 45 grams of cheese. Such quantities rarely cause trouble even for people considered to be lactose intolerant, Professor Wahlqvist said.

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These results go against the medical advice we've been hearing for years (why am I not surprised?). The new advice: High-fat dairy  yes, low-fat dairy no. I also think processed meat (with nitrates) should not be lumped together with unprocessed meat. From Science Daily:

Consumption of high-fat dairy products associated with lower risk of developing diabetes

People with the highest consumption of high-fat dairy products -- eight or more portions per day -- have a 23 percent lower risk of developing type 2 diabetes (T2D) than those with the lowest consumption -- one or less per day, a new study shows.

The study included 26 930 individuals (60% women), aged 45-74 years, from the population-based Malmö Diet and Cancer cohort. Dietary data was collected with a modified diet history method. During 14 years of follow up, 2860 incident T2D cases were identified. 

The researchers found that high intake of high-fat dairy products was associated with a 23% lower incidence of T2D for the highest consuming 20% of participants (or quintile) (median=8 portions/day) compared with the lowest consuming 20% (median=1 portion/day).

In contrast to these findings, there was no association found between intakes of low-fat dairy products and risk of developing type 2 diabetes.

High intakes of meat and meat products were, regardless of fat content, associated with increased risk, but the increased risk was higher for lower fat meats (increased risk of type 2 diabetes for high fat meats 9%, for low fat 24%), both referring to the risk in the highest-consuming versus lowest-consuming 20%). The highest consuming group for the high-fat meat had 90g or more per day, and for the low-fat meat 80g per day.

Same research, some extra details in write-up. From Medscape:

Big Intake of High-Fat Dairy May Be Protective for Diabetes

Previous research led by Nita Forouhi, MD, program leader and public-health physician at the MRC Epidemiology Unit, University of Cambridge, United Kingdom, published in August this year, suggested that molecules with odd numbers of carbon atoms (15 and 17), which are found in dairy products such as yogurt, cheese, and milk, appeared to have a protective effect.

This contrasts with evidence suggesting that even-chain saturated fatty acids, as found in alcohol or margarine, are associated with a greater risk for type 2 diabetes.

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Excerpts from an article by Jane Brody in the NY Times:

Beating Back the Risk of Diabetes

This year, nearly two million American adults and more than 5,000 children and adolescents will learn they have a potentially devastating, life-shortening, yet largely preventable disease: Type 2 diabetes. They will join 29.1 million Americans who already have diabetes.

Diabetes and its complications are responsible for nearly 200,000 deaths a year; the fatality rate among affected adults is 50 percent higher than among similar people without diabetes. Alarmingly, recent studies even have linked diabetes to an increased risk of dementia and Alzheimer's disease. Even people with above-average blood glucose levels, but not diabetes, have an elevated risk.

The Diabetes Prevention Program study, conducted among about 3,800 people who had pre-diabetes, found that moderate weight loss — an average of 12 pounds —  reduced the odds of progression to diabetes by nearly 50 percent.

An excellent discussion of what is known about the effect on diabetes of various foods and supplements appeared recently in Nutrition Action Healthletter at cspinet.org/iceberg.pdf. Some highlights:

Carbohydrates - breads, grains, cereals, sugary drinks and sweets of all kinds — are most problematic for people with diabetes or at risk of developing it. Carbohydrates are eventually metabolized to glucose, which raises the body’s demand for insulin. Consume less of them in general, and choose whole-grain versions whenever possible.

If you must have sweet drinks, select artificially sweetened ones. In two huge studies of nurses and other health professionals who were followed for 22 years, those who drank one or more sugary soft drinks a day had about a 30 percent higher risk of developing diabetes than those who rarely drank them, even after their weight was taken into account.

But there’s good news about coffee. Two or three cups of coffee (but not tea) a day, with or without caffeine, have been consistently linked to a lower risk of Type 2 diabetes. 

For protein, limit consumption of red meat, especially processed meats like sausages, hot dogs and luncheon meats, which are linked to a higher diabetes risk. Instead, choose fish, lean poultry (skinless and not fried), beans and nuts. Low-fat dairy products, including yogurt, and even fatty ones may lower the risk of diabetes; the reason is unclear.

Most protective are green, leafy vegetables — spinach, chard, kale, collards, mustard greens and even lettuce — as well as cruciferous vegetables like cabbage, broccoli and cauliflower. But all vegetables are good and should fill at least two-thirds of your dinner plate.

The nutrients magnesium and vitamin D are also potentially protective. In fact, the preventive value of leafy greens, whole grains, beans and nuts may lie in their high magnesium content. In a well-designed clinical trial of 32 overweight people with insulin resistance, the prelude to diabetes, blood glucose levels and insulin sensitivity improved in those who took a daily magnesium supplement for six months. Don’t go overboard: More than 350 milligrams of magnesium daily can cause diarrhea. 

Vitamin D, long known to be crucial to healthy bones, may also be helpful. In one study of 92 overweight or obese adults with prediabetes, those who took a supplement of 2,000 international units of vitamin D daily had better function of the pancreatic cells that produce insulin..

Of course, how much you weigh and what you eat are not the only concerns. Regular, preferably daily, physical exercise is a vital component of any prevention and treatment program for Type 2 diabetes, or most any chronic ailment. Weight loss can reduce diabetes risk by about 50 percent, but adding exercise to that can lower the odds by 70 percent, compared with people who remain overweight and inactive, according to a study that followed nearly 85,000 female nurses for 16 years. Women who were active for seven or more hours weekly had half the risk of developing diabetes as did women who exercised only a half-hour a week.

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From Science Daily:

High protein diets lead to lower blood pressure, study finds

Adults who consume a high-protein diet may be at a lower risk for developing high blood pressure, concludes a study that found participants consuming the highest amount of protein -- an average of 100 g protein/day -- had a 40 percent lower risk of having high blood pressure compared to the lowest intake level.

One of three U.S. adults has hypertension and 78.6 million are clinically obese, a risk factor for the development of hypertension. Because of the strain that it puts on blood vessel walls, HBP is one of the most common risk factors of stroke and an accelerator of multiple forms of heart disease, especially when paired with excess body weight.

The researchers analyzed protein intakes of healthy participants from the Framingham Offspring Study and followed them for development of high blood pressure over an 11-year period. They found that adults who consumed more protein, whether from animal or plant sources, had statistically significantly lower systolic blood pressure and diastolic blood pressure levels after four years of follow-up. In general, these beneficial effects were evident for both overweight (BMI ≥25 kg/m2) and normal weight (BMI <25 kg/m2) individuals. They also found that consuming more dietary protein also was associated with lower long-term risks for HBP. When the diet also was characterized by higher intakes of fiber, higher protein intakes led to 40-60 percent reductions in risk of HBP.

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Two studies about blood pressure and how it can be easily changed without medications. From Science Daily:

Small weight gain can raise blood pressure in healthy adults

Gaining a few pounds can increase blood pressure in healthy adults, researchers report. Increased fat inside the abdomen led to even larger increases in blood pressure, their study results showed. Many people understand the health dangers of large amounts of extra body weight, but researchers in this study wanted to see the impact of a small weight gain of about five to 11 pounds.

At the beginning of the eight-week study, a 24-hour monitor tested the blood pressure of 16 normal weight people. Their results were compared to 10 normal weight, healthy people who maintained the same weight over the eight weeks. Researchers found: -Those who gained weight had a systolic blood pressure (top number) increase from an average 114 mm Hg to an average 118 mm Hg. -Those who gained more weight inside their abdomen had a greater blood pressure increase. -A five to 11 pound weight gain didn't change cholesterol, insulin or blood sugar levels. The study was conducted in healthy people ages 18-48. 

From Science Daily:

Restricting calories may improve sleep apnea, blood pressure in obese people

Restricting calories may improve sleep apnea and reduce blood pressure in obese adults. Those who restricted their calories had higher levels of oxygen in their blood and a greater reduction in body weight, a study has demonstrated.

 "Losing weight was most likely the key to all the benefits observed in the calorie-restricted group. A greater reduction in systolic blood pressure can be explained, at least partially, by the reduction in body weight that was associated with reduction in obstructive sleep apnea severity and sympathetic nervous system activity." Systolic blood pressure is the top number in a blood pressure reading, which measures the force of the blood in the arteries when the heart is contracted.

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A banana a day keeps the doctor away? A recent large study found that older women who eat foods with higher amounts of potassium may be at lower risk of stroke and death, when compared to women who eat fewer potassium rich foods. The association was with ischemic stroke (caused by clot) and not hemorrhagic stroke.

Some good food sources of potassium are: bananas, cantaloupe, grapefruit, oranges, white and sweet potatoes, and white beans. The U.S. Department of Agriculture recommends that women eat at least 4700 mg of potassium daily, but in this study the average intake of the postmenopausal women was 2611 mg per day.

This study followed  90,137 postmenopausal women (aged 50 to 79 years at baseline), and followed them an average of 11 years. Now this same study needs to be done with men and women of all ages. From Science Daily:

Potassium-rich foods cut stroke, death risks among older women

Older women who eat foods with higher amounts of potassium may be at lower risk of stroke and death than women who consume less potassium-rich foods. The health benefits from potassium-rich foods are greater among older women who do not have high blood pressure. Most older American women do not eat the recommended amounts of potassium from foods.

"Our findings give women another reason to eat their fruits and vegetables. Fruits and vegetables are good sources of potassium, and potassium not only lowers postmenopausal women's risk of stroke, but also death."

Researchers studied 90,137 postmenopausal women, ages 50 to 79, for an average 11 years. They looked at how much potassium the women consumed, as well as if they had strokes, including ischemic and hemorrhagic strokes, or died during the study period. Women in the study were stroke-free at the start and their average dietary potassium intake was 2,611 mg/day. Results of this study are based on potassium from food, not supplements.

The researchers found: -Women who ate the most potassium were 12 percent less likely to suffer stroke in general and 16 percent less likely to suffer an ischemic stroke than women who ate the least. -Women who ate the most potassium were 10 percent less likely to die than those who ate the least. They also said there was no evidence of any association between potassium intake and hemorrhagic stroke, which could be related to the low number of hemorrhagic strokes in the study.

The U.S. Department of Agriculture recommends that women eat at least 4,700 mg of potassium daily. "Only 2.8 percent of women in our study met or exceeded this level. "Our findings suggest that women need to eat more potassium-rich foods. You won't find high potassium in junk food. Some foods high in potassium include white and sweet potatoes, bananas and white beans."

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The great effects (especially for hemorrhagic stroke) were found in people eating just 1 1/2 portions of fresh fruit daily. The amazing part is that 6.3% admitted to never consuming fruit. From Science Daily:

Fruit consumption cuts cardiovascular disease risk by up to 40 percent

Daily fruit consumption cuts the risk of cardiovascular disease (CVD) by up to 40 percent, according to research. The findings from the seven-year follow-up study of nearly a half million people in the China Kadoorie Biobank found that the more fruit people ate, the more their risk of CVD declined.

Dr Du said: "CVD, including ischaemic heart disease (IHD) and stroke, is the leading cause of death worldwide. Improving diet and lifestyle is critical for CVD risk reduction in the general population but the large majority of this evidence has come from western countries and hardly any from China."

The current study included 451 681 participants with no history of CVD and not on anti-hypertensive treatment at baseline from the China Kadoorie Biobank(1) conducted in 10 different areas of China, 5 rural and 5 urban. Habitual consumption of fruit was recorded at baseline according to five categories: never, monthly, 1-3 days per week, 4-6 days per week, daily.

Over the seven year follow up period there were 19 300 cases of IHD and 19 689 strokes (14 688 ischaemic and 3562 haemorrhagic). Some 18% of participants consumed fruit daily and 6.3% never consumed fruit. The average amount of fruit eaten by the daily consumers was 1.5 portions (~150g).

The researchers found that compared to people who never ate fruit, those who ate fruit daily cut their CVD risks by 25-40% (around 15% for IHD, around 25% for ischaemic stroke and 40% for haemorrhagic stroke). There was a dose response relationship between the frequency of fruit consumption and the risk of CVD.

Dr Du said: "Our data clearly shows that eating fresh fruit can reduce the risk of cardiovascular disease, including ischaemic heart disease and stroke (particularly haemorrhagic stroke). And not only that, the more fruit you eat the more your CVD risk goes down. It does suggest that eating more fruit is beneficial compared to less or no fruit."

The researchers also found that people who consumed fruit more often had significantly lower blood pressure (BP). Eating fruit daily was associated with 3.4/4.1 mmHg lower systolic/diastolic BP compared to those who never ate fruit. 

In a separate analysis, the researchers examined the association of fruit consumption with total mortality and CV mortality in more than 61,000 patients from the China Kadoorie Biobank who had CVD or hypertension at baseline. They found that compared to those who never ate fruit, daily consumers of fruit cut their overall risk of death by 32%. They also reduced their risks of dying from IHD by 27% and from stroke by around 40%.

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Unfortunately the first article doesn't list the herbal supplements causing liver problems, but the earlier NY Times article mentions green tea extracts as one of them. From Science Daily:

Liver injury caused by herbals, dietary supplements rises in study population

Liver injury caused by herbals and dietary supplements increased from 7% to 20% in a U.S. study group over a ten-year period, research shows. According to the study, liver injury caused by non-bodybuilding supplements is most severe, occurring more often in middle-aged women and more frequently resulting in death or the need for transplantation than liver injury from bodybuilding supplements or conventional medications.

In response to the need for research in this area, the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK) supported the establishment of the Drug-Induced Liver Injury Network (DILIN) in 2003 to track cases of liver injury caused by medications (excluding acetaminophen (Tylenol®)), herbals, and dietary supplements. Herbals and dietary supplements were identified as the second most common cause of liver injury in the first DILIN report.

The present study examines hepatotoxicity due to supplements compared to medications, enrolling 839 patients with liver injury from 8 U.S. DILIN referral centers between 2004 and 2013 While bodybuilding supplements caused prolonged jaundice (median 91 days) in young men, no fatalities or liver transplantations occurred. Death or liver transplantation occurred more frequently among cases of injury from non-bodybuilding supplements, 13%, than from conventional medications, 3%. Liver injury from non-bodybuilding supplements was more common in middle aged women.

From NY Times (Dec. 2013):

Spike in Harm to Liver Is Tied to Dietary Aids

But the supplement business is largely unregulated. ... But a federal law enacted in 1994, the Dietary Supplement Health and Education Act, prevents the Food and Drug Administration from approving or evaluating most supplements before they are sold. Usually the agency must wait until consumers are harmed before officials can remove products from stores. Because the supplement industry operates on the honor system, studies show, the market has been flooded with products that are adulterated, mislabeled or packaged in dosages that have not been studied for safety.

The new research found that many of the products implicated in liver injuries were bodybuilding supplements spiked with unlisted steroids,and herbal pills and powders promising to increase energy and help consumers lose weight.

 More popular supplements like vitamins, minerals, probiotics and fish oil had not been linked to “patterns of adverse effects,” he said.

Since 2008, the F.D.A. has been taking action against companies whose supplements are found to contain prescription drugs and controlled substances, said Daniel Fabricant, the director of the division of dietary supplement programs in the agency’s Center for Food Safety and Applied Nutrition. For example, the agency recently took steps to remove one “fat burning” product from shelves, OxyElite Pro, that was linked to one death and dozens of cases of hepatitis and liver injury in Hawaii and other states.

A second trend emerged when Dr. Navarro and his colleagues studied 85 patients with liver injuries linked to herbal pills and powders. Two-thirds were middle-aged women, on average 48 years old, who often used the supplements to lose weight or increase energy. Nearly a dozen of those patients required liver transplants, and three died

But one product that patients used frequently was green tea extract, which contains catechins, a group of potent antioxidants that reputedly increase metabolism. The extracts are often marketed as fat burners, and catechins are often added to weight-loss products and energy boosters. Most green tea pills are highly concentrated, containing many times the amount of catechins found in a single cup of green tea, Dr. Bonkovsky said. In high doses, catechins can be toxic to the liver, he said, and a small percentage of people appear to be particularly susceptible.

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Two write-ups about the same large study.The good news is that there is no one diet that works - the key is to stick with the diet. From Science Daily:

Comparison of named diet programs finds little difference in weight loss outcomes

In an analysis of data from nearly 50 trials including about 7,300 individuals, significant weight loss was observed with any low-carbohydrate or low-fat diet, with weight loss differences between diet programs small, findings that support the practice of recommending any diet that a patient will adhere to in order to lose weight.

Bradley C. Johnston, Ph.D., of the Hospital for Sick Children Research Institute, Toronto, and McMaster University, Hamilton, Ontario, and colleagues conducted a meta-analysis to assess the relative effectiveness of different popular diets in improving weight loss. 

The meta-analysis included 59 articles that reported 48 randomized clinical trials (7,286 individuals; median age, 46 years; median weight, 207.5 lbs.). In the diet-class analysis adjusted for exercise and behavioral support, all treatments were superior to no diet at 6-month follow-up. Compared with no diet, low-carbohydrate diets had a median difference in weight loss of 19.2 lbs. and low-fat diets had similar estimated effects (17.6 lbs.).

At 12-month follow-up, the estimated average weight losses of all diet classes compared with no diet were approximately 2.2 to 4.4 lbs. less than after 6-month follow-up. The diet classes of low fat (16 lbs.) and low carbohydrate (16 lbs.) continued to have the largest estimated treatment effects.

Weight loss differences between individual diets were minimal. "Our findings should be reassuring to clinicians and the public that there is no need for a one-size-fits­ all approach to dieting because many different diets appear to offer considerable weight loss benefits. 

From Medical Xpress:

Any diet works, if you stick to it, study finds

At six month follow-up, people on low-carbohydrate diets lost 19 more pounds than those who were not on a diet, while those on low-fat diets lost 17 more pounds than those on no diet. After 12 months about two to three pounds of that difference was gone, and there was no difference between low-carbohydrate and low-fat diets.

Behavioural support in a diet made a difference at six months, enhancing weight loss by about seven pounds, while exercise was significant at 12 months, improving weight loss by about four and half pounds.