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Category: nutrition

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Are probiotic bacteria the reason?

From Medical Xpress: Does a yogurt a day keep diabetes away?

A high intake of yogurt has been found to be associated with a lower risk of developing type 2 diabetes, according to research published in open access journal BMC Medicine. This highlights the importance of having yogurt as part of a healthy diet.

Type 2 diabetes is a chronic condition that occurs when the body doesn't produce enough insulin, or the body's cells develop resistance to insulin. There is an increased risk of developing it if a relative has the condition or if an individual has an unhealthy lifestyle. 

Researchers from Harvard School of Public Health pooled the results of three prospective cohort studies that followed the medical history and lifestyle habits of health professionals. These studies were the Health Professionals' Follow-up Study (HFPS), which included 51,529 US male dentists, pharmacists, vets, osteopathic physicians and podiatrists, aged from 40 to 75 years; Nurses' Health Study (NHS), which began in 1976, and followed 121,700 female US nurses aged from 30 to 55 years; and Nurses' Health Study II (NHS II), which followed 116,671 female US nurses aged from 25 to 42 years beginning in the year 1989.

Within the three cohorts 15,156 cases of type 2 diabetes were identified during the follow-up period. The researchers found that the total dairy consumption had no association with the risk of developing type 2 diabetes. They then looked at consumption of individual dairy products, such as skimmed milk, cheese, whole milk and yogurt. When adjusting for chronic disease risk factors such as age and BMI as well as dietary factors, it was found that high consumption of yogurt was associated with a lower risk of developing type 2 diabetes.

The authors then conducted a meta-analysis, incorporating their results and other published studies, up to March 2013, that investigated the association between dairy products and type 2 diabetes. This found that consumption of one 28g serving of yogurt per day was associated with an 18 per cent lower risk of type 2 diabetes.

Previous research has suggested calcium, magnesium, or specific fatty acids present in dairy products may lower the risk of type 2 diabetes. It has been shown that probiotic bacteria found in yogurt improves fat profiles and antioxidant status in people with type 2 diabetes and the researchers suggest this could have a risk-lowering effect in developing the condition. 

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Big question: will vitamin D supplementation prevent cognitive decline? And what should be a daily supplement dose for adults? An earlier post cited a Medscape article suggesting that taking 1000 IU of vitamin D3 daily would be a good daily level of supplementation. From Medscape:

Vitamin D Deficiency Predicts Cognitive Decline

A new study supports a link between low levels of vitamin D and increased risk for cognitive decline, prompting calls for clinical trials to test whether vitamin D supplementation may delay or prevent dementia. In a group of cognitively intact older adults, serum 25-hydroxyvitamin D (25OHD) levels below 75 nmol/L at the outset predicted cognitive decline over roughly the next 4 years, independent of other factors.

For this analysis, the researchers looked at data on 1927 community-dwelling elderly individuals (mean age, 73.9 years) participating in the Italian population-based cohort study, Progetto Veneto Anziani (Pro.V.A.).

Dr Toffanello and colleagues say studies are needed to evaluate whether vitamin D supplementation might help to delay the cognitive decline, especially in patients who already have cognitive impairment.

David J. Llewellyn, PhD, from the University of Exeter Medical School in the United Kingdom, who has studied vitamin D and cognitive function but wasn't involved in this study, agrees. He told Medscape Medical News that this new study "effectively replicates" a 2010 study by his group showing a link between low vitamin D levels and an increased risk for cognitive decline. He said the Pro.V.A . study results are also consistent with a study his group published just this year inNeurology. That study suggested older patients with vitamin D levels below 50 nmol/L have about a 122% increased risk for dementia compared with those with higher levels.

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Two studies that talk about a healthy diet and health benefits.From Science Daily:

Home cooking a main ingredient in healthier diet, study shows

People who frequently cook meals at home eat healthier and consume fewer calories than those who cook less, according to new Johns Hopkins Bloomberg School of Public Health research."When people cook most of their meals at home, they consume fewer carbohydrates, less sugar and less fat than those who cook less or not at all -- even if they are not trying to lose weight," says Julia A. Wolfson, MPP, a CLF-Lerner Fellow at the Johns Hopkins Center for a Livable Future and lead author of the study.The findings also suggest that those who frequently cooked at home -- six-to-seven nights a week -- also consumed fewer calories on the occasions when they ate out.

Wolfson and co-author Sara N. Bleich, PhD, an associate professor in the Department of Health Policy and Management at the Bloomberg School, analyzed data from the 2007-2010 National Health and Nutrition Examination Survey from more than 9,000 participants aged 20 and older... The researchers found that 8 percent of adults cooked dinner once or less a week and this group consumed, on an average day, 2,301 total calories, 84 grams of fat and 135 grams of sugar. Forty-eight percent of participants cooked dinner six to seven times a week and they consumed 2,164 calories, 81 grams of fat and 119 grams of sugar on an average day.

The research found blacks are more likely to live in households where cooking occurs less frequently than whites; and individuals who work more than 35 hours a week outside the home also cook less often.

From Medical Xpress:

Healthy diets are good for the kidneys

A healthy diet may help protect the kidneys, according to two studies that will be presented at ASN Kidney Week 2014 November 11¬-16 at the Pennsylvania Convention Center in Philadelphia, PA. Dietary modifications may be a low-cost, simple intervention to reduce the burden of chronic kidney disease (CKD). 

A higher-quality diet, as measured using 3 different scoring systems for dietary qualities known to reduce the risk of cardiovascular disease, was associated with a 16% to 23% reduced risk of needing dialysis or dying from kidney problems. Higher-quality diets included those high in fruits, vegetables, and unsaturated fats. The researchers also found that high sodium intake (average of 4.7g g/day) was linked with an increased risk of needing dialysis or dying from kidney problems, but no benefit was seen for low sodium intake (average 2.0 g/day) compared with moderate intake. In contrast, high potassium intake was associated with a reduced future risk.

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Get your omega-3 fatty acids from either fish or flaxseed (or other seeds).From Science Daily:

Nothing fishy about health benefits of plant-based omega-3 fatty acid

Increasing the amount of omega-3s in your diet, whether from fish or flax, will likely decrease your risk of getting heart disease, according to Penn State nutritionists. A substantial amount of evidence exists supporting the heart-health benefits of eicosapentaenoic acid and docosahexaenoic acid (EPA and DHA), marine-derived omega-3 fatty acids. However, much less evidence exists to demonstrate the positive effects of alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid.

EPA and DHA can be found in seafood and fish oil, and are often consumed in the form of dietary supplements. ALA is found in flaxseed and its oil, vegetable oils, and some nuts, and is now available in supplement form. EPA and DHA have been available for much longer. Other sources of ALA, EPA and DHA are fortified foods such as orange juice, eggs, peanut butter, margarine and bread, among others. While there are many other omega-3 fortified foods in the market place, most are relatively low in omega-3 fatty acids.

Omega-3 fatty acids are considered essential for human health, but the body does not produce them -- therefore they must be consumed in order to maintain appropriate levels.

In reviewing existing literature on the subject, the researchers have come to the conclusion that ALA is likely just as effective in preventing cardiovascular disease as EPA and DHA have proven to be, as they report on the current issue of Advances in Nutrition.

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This article describes results of a research review showing cancer prevention benefits from eating fatty fish and fish oil. From Science News:

Marked benefits found for cancer prevention with a higher intake of fatty fish

A new research review will once again have people asking for a second helping of wild Alaskan salmon at the dinner table. While several other studies have recently challenged the long-held belief of the benefits of a diet high in omega-3 fatty acids, this new study cites compelling evidence that eating the right kinds of fatty fish, in the right quantity, and prepared the right way, can in fact help prevent the body’s development of adenocarcinomas, a common type of cancerous tumor. A high proportion of the cancers arising in the breast, prostate, pancreas, colon, and the rest of the gastrointestinal tracts are adenocarcinomas.

The authors first cite evidence that the recently-demonstrated ability of daily low-dose aspirin to decrease risk for adenocarcinomas is attributable to its ability to modestly decrease the activity of cyclooxygenase-2 (cox-2), an enzyme which contributes importantly to the genesis and progression of adenocarcinomas. They then propose that an ample dietary intake of omega-3 fats -- the type prominent in fatty fish -- could also be expected to oppose cox-2 activity, and thereby reduce risk for adenocarcinomas.

The authors emphasize that it is not only the amount of fish consumed daily, but also the nature of this fish, and how it is preserved or cooked, that can have a major impact on the potential of dietary fish to lower cancer risk. "An easy way to see the benefit of omega-3 is to look at Italy," Dr. DiNicolantonio said. "The staple oil used in cooking and as a salad dressing in Italy is olive oil, which is quite low in omega-6. Meanwhile, fish -- high in omega-3 -- is a staple food in the Italian diet, and this fish is rarely salt-preserved or fried. In Italians studies, subjects who consumed fish at least twice weekly as compared to those who ate fish less than once a week, were found to be at a significantly lower risk for a number of cancers, including ovarian, endometrial, pharyngeal, esophageal, gastric, colonic, rectal, and pancreatic."

The authors also focus on several recent studies in which regular consumption of fish oil is correlated with lower subsequent cancer risk. These studies have reported lower risks for colorectal, breast, and advanced prostate cancer in those taking such supplements. And a recent study from the University of Washington, which estimated total omega-3 intakes of its subjects from both fish and from supplements, found that a high omega-3 intake was associated with a 23 percent reduction in total cancer mortality. Indeed, mortality from all causes was significantly lower in those with higher omega-3 intakes. The authors also noted that cox-2 is significantly expressed in pre-malignant and early stage adenocarcinomas, but expression is sometimes lost as cancers mature. This may be why cox-2 inhibition (via increased omega-3 intake) seems to have greater potential for cancer prevention, than for cancer therapy.

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Lasting benefits from lifestyle changes (Mediterranean diet and exercise). From Science Daily:

Mediterranean diets have lasting health benefits

The health benefits of switching to a Mediterranean style diet and upping the amount of time spent exercising for a period of just eight weeks can still be seen a year after stopping the regime, a new study has shown.

The research by Sheffield Hallam University and the University of Lincoln in the UK revealed that the diet and exercise combination leads to improved blood flow in cells in the inner lining of the blood vessels -- called the endothelial cells -- a full 12 months after completing participation in the intervention programme.

Endothelial cells line the interior of the entire vascular system of the human body -- from the large arteries to the smallest capillaries -- and improvements in their function could reduce the risk of people developing cardiovascular disease, the study said.

Researchers believe the long-term health benefits observed after such a short intervention could be due to molecular changes associated with the Mediterranean diet. Traditional Mediterranean cuisine is based on olive oil, fruit, vegetables and salad, fish, legumes, whole grain foods, wine and limited consumption of red meat.

The study focused on healthy people over the age of 50. Participants were originally assessed over an eight-week period.One group was encouraged to eat more vegetables, fruit, olive oil, tree nuts and fresh oily fish, as well as take up a moderate exercise regime, while the other just took up exercise alone.

The results showed more health improvements in the Mediterranean diet group than the exercise only group, which one year later, were still evident despite the lifestyle changes implemented during the study no longer being carefully followed.

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Published on 1 Comment on Vegan Diet May Be Best For Weight Loss

I think many will say: Oh no! Totally vegan is best for weight loss?? From Science Daily:

Vegan diet best for weight loss even with carbohydrate consumption, study finds

People shed more weight on an entirely plant based diet, even if carbohydrates are also included, a study has concluded. Other benefits of eating a vegan diet include decreased levels of saturated and unsaturated fat, lower BMIs, and improved macro nutrients.

The study, conducted by the university's Arnold School of Public Health and published in The International Journal of Applied and Basic Nutritional Sciences, compared the amount of weight lost by those on vegan diets to those on a mostly plant-based diet, and those eating an omnivorous diet with a mix of animal products and plant based foods. At the end of six months, individuals on the vegan diet lost more weight than the other two groups by an average of 4.3%, or 16.5 pounds.

The study followed participants who were randomly assigned to one of five diets on the dietary spectrum: vegan which excludes all animal products, semi-vegetarian with occasional meat intake; pesco-vegetarian which excludes all meat except seafood; vegetarian which excludes all meat and seafood but includes animal products, and omnivorous, which excludes no foods.

Participants followed their assigned dietary restrictions for six months, with all groups except the omnivorous participating in weekly group meetings. Those who stuck to the vegan diet showed the greatest weight loss at the two and six month marks.The lead author on this study, Gabrielle Turner-McGrievy notes that the diet consumed by vegan participants was high in carbohydrates that rate low on the glycemic index. 

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Take note: research has linked a lack of microbial diversity in human guts to various diseases. A solution: Eat more plants! From Science Daily:

Compared with apes, people's gut bacteria lack diversity, study finds

The microbes living in people's guts are much less diverse than those in humans' closest relatives, the African apes, an apparently long evolutionary trend that appears to be speeding up in more modern societies, with possible implications for human health, according to a new study.

Based on an analysis of how humans and three lineages of ape diverged from common ancestors, researchers determined that within the lineage that gave rise to modern humans, microbial diversity changed slowly and steadily for millions of years, but that rate of change has accelerated lately in humans from some parts of the world.

People in nonindustrialized societies have gut microbiomes that are 60 percent different from those of chimpanzees. Meanwhile, those living in the U.S. have gut microbiomes that are 70 percent different from those of chimps.

 "On the other hand, in apparently only hundreds of years -- and possibly a lot fewer -- people in the United States lost a great deal of diversity in the bacteria living in their gut."

That rapid change might translate into negative health effects for Americans. Previous research has shown that compared with several populations, people living in the U.S. have the lowest diversity of gut microbes. Still other research has linked a lack of microbial diversity in human guts to various diseases such as asthma, colon cancer and autoimmune diseases.

One possible explanation for humans evolving to have less diversity in their gut microbiomes is that they shifted to a diet with more meat and fewer plants. Plants require complex communities of microbes to break them down, which is not as true for meat.

As for why Americans have experienced much more rapid changes in microbial diversity compared with people in less industrialized societies, some experts have suggested more time spent indoors, increased use of antibacterial soaps and cleaners, widespread use of antibiotics and high numbers of births by Cesarean section all may play a role. Antibiotics and antimicrobial cleaners can kill good bacteria along with the bad, and C-section deliveries prevent babies from receiving certain bacteria from the mother typically conferred during vaginal births.

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Red meat,bacteria, and atherosclerosis.From Medical Xpress:

Why does red meat increase the risk for cardiovascular disease? Blame our gut bacteria

New research provides details on how gut bacteria turn a nutrient found in red meat into metabolites that increase the risk of developing heart disease. Publishing in the November 4th issue of the journal Cell Metabolism, the findings may lead to new strategies for safeguarding individuals' cardiovascular health.

Previous research led by Dr. Stanley Hazen, of Lerner Research Institute and the Miller Family Heart and Vascular Institute at Cleveland Clinic, revealed a pathway by which red meat can promote atherosclerosis, or hardening of the arteries. Essentially, bacteria in the gut convert L-carnitine, a nutrient abundant in red meat, into a compound called trimethylamine, which in turn changes to a metabolite named trimethylamine-N-oxide (TMAO), which promotes atherosclerosis. Now Dr. Hazen and his team extend their earlier research and identify another metabolite, called gamma-butyrobetaine, that is generated to an even greater extent by gut bacteria after L-carnitine is ingested, and it too contributes to atherosclerosis.

The discovery that metabolism of L-carnitine involves two different gut microbial pathways, as well as different types of bacteria, suggests new targets for preventing atherosclerosis—for example, by inhibiting various bacterial enzymes or shifting gut bacterial composition with probiotics and other treatments.

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An amazing and unforgettable story of a man researching the gut microbes that are increasingly lost in developed Westernized populations. And do go read the original story (see link).From Popular Science:

Scientist Gives Himself Fecal Transplant To Try A Hunter-Gatherer's Microbiome

Why a field researcher from America has exposed his colon to the gut microbiome of a tribesman from Tanzania.

It's not often we encounter a story that begins with a line like this: “AS THE SUN set over Lake Eyasi in Tanzania, nearly thirty minutes had passed since I had inserted a turkey baster into my bum and injected the feces of a Hadza man – a member of one of the last remaining hunter-gatherer tribes in the world – into the nether regions of my distal colon.”

The guy behind this essay, Jeff Leach, is part of a multi-national scientific research team that by his account has been living with the Hadza, hunter-gatherers in Tanzania, for over a year. They have collected hundreds of samples from humans, animals, and the environment in order to observe how the microbial communities in and around the Hadza change with the dramatic seasonal weather shifts in East Africa: six months of near-steady rain followed by six dry months.

The question driving the research is “what a normal or healthy microbiome might have looked like before the niceties and medications of late whacked the crap out of our gut bugs in the so-called modern world,” Leach writes.

The Hadza are contemporary people, Leach writes, not an undiscovered stone-age civilization. But they're excellent subjects for this research because they still live on plant and animal foods that humans have hunted and gathered for millennia, and their use of western medications is extremely limited.

The health impacts of what lives (or doesn't) in our guts are getting increased attention in Western dietary and medical circles -- and eating foods containing "probiotics" just scratches the surface. Recent research suggests that use of antibiotics may be fundamentally altering our gut biomes for the worse, increasing rates of allergies, asthma and weight gain.

As for fecal transplants, they're no longer career killers in polite medical conversation. Swapping poop from healthy to sick persons is now an up-and-up treatment for curing chronic gastrointestinal disease. The launch of the OpenBiome fecal transplant bank in the U.S. earlier this year seems to signal that the technique is going mainstream.

As for Jeff Leach, he describes his primary scientific motivation for self-administering a fecal transplant as testing the hypothesis "of microbial extinction, something I believe we all suffer from in the western world and may be at the root of what’s making us sick." The biggest change Leach and his girlfriend have noticed since the transplant is that he's passing a lot less gas. 

Read the rest of his very readable, informative and down-to-earth essay: (Re)Becoming Human: what happened the day I replaced 99% of the genes in my body with that [sic] of a hunter-gatherer.