Long-awaited vitamin D studies are finally appearing this year. A large international study found that higher levels of vitamin D in a person's blood is associated with a lower risk of colorectal cancer. Those with the highest vitamin D levels had a 21% lower risk (compared to the lowest group) of colorectal cancer after an average 5.5 years.
But the researchers generally do not recommend vitamin D supplements - saying that most people had adequate levels from foods and sunshine. However, they suggest that the risk for vitamin D deficiency is higher for those with very dark skin; for older adults (their skin may not be as efficient at synthesizing vitamin D); and for those who do not go outside at all - and that these groups may need supplementation (but not beyond 4000 IU per day - because higher levels have negative health effects). From Medical Xpress:
Large international study links blood vitamin D levels to colorectal cancer risk
A new study authored by scientists from the American Cancer Society, the Harvard T.H. Chan School of Public Health, the U.S. National Cancer Institute, and more than 20 other medical centers and organizations finds that higher circulating vitamin D concentrations are significantly associated with lower colorectal cancer risk. This study strengthens the evidence, previously considered inconclusive, for a protective relationship. Optimal vitamin D concentrations for colorectal cancer prevention may be higher than the current National Academy of Medicine recommendations, which are based only on bone health. ...continue reading "Vitamin D and Colorectal Cancer Risk"
There has been a lot of concern with the rising incidence of type 2 diabetes in the US and other countries. Along with that is an interest in blood glucose levels after meals (postprandial blood glucose response or PBGR). Glucose is a type of sugar that slightly rises after a meal, and some types of foods rise it more than others. It is thought that big spikes in glucose levels in the blood are unhealthy for both long-term health and also if one has diabetes. A nicely done Canadian study (people randomly assigned to groups) found that swapping out half of a portion of starchy potatoes or rice with lentils reduced levels of blood glucose levels by 20% (when replacing rice) to 35 % (replacing potatoes).
What foods are pulses? Pulses are dried seeds of legume plants, and include all lentils, dry beans, and dry peas. This includes, baked beans, all lentils (red, green, yellow, brown), chickpeas (garbanzo beans), black-eyed peas, runner beans, fava beans, kidney beans, lima beans, haricots, cannellini beans, pinto beans, etc. They provide fiber in the diet and are a great source of protein. From Science Daily: Lentils significantly reduce blood glucose levels
Replacing potatoes or rice with pulses can lower your blood glucose levels by more than 20 per cent, according to a first-ever University of Guelph study. Prof. Alison Duncan, Department of Human Health and Nutritional Sciences, and Dan Ramdath of Agriculture and Agri-Food Canada, found that swapping out half of a portion of these starchy side dishes for lentils can significantly improve your body's response to the carbohydrates. ...continue reading "Eating Lentils Has Health Benefits"
Once again, a study linked a person's diet with the chances of getting age-related macular degeneration (AMD). Macular degeneration is a leading cause of vision loss in Americans 60 years and older, and it has no cure. The study (conducted at the University of Bordeaux, France) found that people who eat a Mediterranean diet are less likely to develop advanced age-related macular degeneration. The study was presented at a conference (not a medical journal), but it builds on other research with similar findings.
What is the Mediterranean diet? It is a diet rich in fruits, vegetables, whole grains, legumes (beans), nuts, seeds, olive oil, and fish. The diet is a good source of fiber, omega-3 polyunsaturated fatty acids (especially fatty fish such as salmon, mackerel, and sardines), and of vitamin C, vitamin E, lutein, zeaxanthin, zinc, and copper. Lutein and zeaxanthin are carotenoids found in green, yellow and red vegetables. From Medscape:
Mediterranean Diet Linked With Lower Incidence of Advanced AMD
People who eat a Mediterranean diet are less likely to develop advanced age-related macular degeneration (AMD). That's according to research presented May 1 at ARVO 2018, the annual meeting of the Association for Research in Vision and Ophthalmology, in Honolulu, Hawaii. "Higher adherence to the Mediterranean diet was associated with a 39% reduced risk of developing advanced AMD. These results highlight that eating a healthy diet, such as a Mediterranean-type diet, may help to limit progression to advanced AMD," Dr. Benedicte M. J. Merle of the University of Bordeaux, France, and her colleagues write in their abstract. ...continue reading "Mediterranean Diet Linked to Lower Risk of Macular Degeneration"
Another study has found that the most common vitamin and mineral supplements (multivitamins, vitamin D, calcium, and vitamin C), don't offer hoped for health benefits, and may actually carry some risks. This latest study was a review of other studies, and examined whether specific vitamins or minerals would lower the risk of cardiovascular disease (including heart attacks and strokes) and death from any cause (referred to as all cause mortality"). [Posts discussing other research finding problems with supplements.]
In general, the review of studies of popular supplements (multivitamins, vitamin D, calcium, and vitamin C) show no consistent benefit (no significant effect) for the prevention of cardiovascular disease, heart attacks, or stroke, nor any lowering of death (all cause mortality). On the other hand, folic acid and B-vitamins with folic acid, B6, and B12 reduced stroke (folic acid showed a 20% reduction in stroke), but niacin and antioxidants were associated with an increased risk of death from any cause (10% increase). But overall the effects in the studies were small. Vitamin D did not show any benefits in reducing death, but the researchers pointed out that many vitamin D studies are now under way, and the results of vitamin D studies so far are mixed (e.g. 16 showing positive effects from vitamin D, 17 showing a more favorable effect in the control group, and 10 neither).
On the other hand, the researchers stressed that eating a well balanced diet has lots of health benefits and is recommended by the U.S. Dietary Guidelines Advisory Committee. Three dietary patterns are frequently discussed as beneficial: 1) a healthy American diet (sometimes called a "prudent diet") low in saturated fat, trans fat, and red meat, but high in fruit and vegetables, 2) a Mediterranean diet, and 3) a vegetarian diet. All 3 of these diets are rich in fruits and vegetables (which means increased fiber), are relatively rich in vitamins and minerals, and meet Dietary Reference Intake guidelines. ...continue reading "Study Finds No Benefit From Most Supplements"
Something a little different today. For years I've posted studies showing that eating organic foods lowers pesticide levels in the body quickly, eating organic foods is the only way to avoid the presence of the controversial pesticide glyphosate (Roundup) in food, the nutritional profile (especially fatty acids) of meat and milk from grass-fed, pasture raised animals is different and healthier than conventionally raised animals (and even organic animals not raised on pasture), and on and on. In other words, eating organic foods has health benefits. All good.
But meanwhile, the National Organic Program and National Organic Standards Board (which controls the national organic foods certification program) is being influenced by big agriculture lobbying - to the dismay of real organic farmers. Yes - real organic farmers, who farm the way we expect our organic meat and crops to be raised. You know - cows grazing outside, chickens pecking away for insects outside, crops being raised in real soil (and not hydroponics). But ... Big Agriculture with the mega-farms and lots of chemicals, and animals confined by the thousands indoors, have decided they want a piece of the organic action, and have now influenced the National Organic Program and National Organic Standards Board with the result of weakening of organic standards. But there are other problems too with the organic program as it currently exists.
The Washington Post did a series of articles last year about a huge issue of fraud - about how so-called organic food from other countries may really not be organic (esp. corn and soybeans), and this mega-influx of fake organic food with lower prices is something real organic farmers in the US can't compete with. Also, how "larger agricultural companies have sought to loosen organic rules in the name of efficiency and affordability". The organic market is a big one, and growing bigger every year (billions of $$). It benefits large corporations and huge mono-crop farms financially to have watered down standards.
Another example: the organic milk that one buys may not really be organic (and the same issue with organic chickens). Organic dairies are supposed to have their dairy cows out grazing in the pasture for a minumum of 120 days per year - it is a requirement. But big dairies that are only organic in name ignore that requirement - such as the huge Aurora Dairy. Yup, they lie. And in September 2017, the USDA (US Department of Agriculture) didn't punish the 15,000 cow Aurora Dairy - instead they "exonerated the enormous Aurora Dairy CAFO (Confinement Animal Feeding Operation) of any wrongdoing at their Colorado “farm.” This dairy operation was described in detail in one Washington Post article, along with compelling test results to prove the cattle weren’t on pasture." So of course now they and other mega-dairies will just ignore the organic regulations, because they can without any penalty. ...continue reading "Is A New Organic Label Needed For Farmers Following Traditional Organic Practices?"
Once again, a study finds that consumption of nuts is beneficial to health - this time by impacting the gut microbiome (community of microbes) in a beneficial way. This was a nicely done study -18 healthy adults randomly assigned first to either eating about a handful of walnuts daily (42 g) or zero nuts daily for 3 weeks, and then assigned to the other group for 3 weeks, with a "washout period" of 1 week in-between. Walnut consumption resulted in higher amounts of beneficial gut bacteria (Faecalibacterium, Clostridium, Dialister, and Roseburia) which are butyrate producing (beneficial!), and lowering of proinflammatory secondary bile acids and LDL cholesterol (both beneficial).
As seen in this walnut study from the University of Illinois, adding walnuts to the diet has quick effects on the gut microbiome. Other studies find that diets rich in nuts (which are a source of dietary fiber and unsaturated fatty acids) are associated with a reduced risk of death from cancer and heart disease. Bottom line: eating some nuts daily feeds beneficial bacteria in the gut, and so has beneficial health effects. This walnut study had everyone eating about a handful of walnut halves a day (42 g, which is a little less than 1/2 cup walnut halves).
From Science Daily: Walnuts impact gut microbiome and improve health
Diets rich in nuts, such as walnuts, have been shown to play a role in heart health and in reducing colorectal cancer. According to a new study from the University of Illinois, the way walnuts impact the gut microbiome -- the collection of trillions of microbes or bacteria in the gastrointestinal tract -- may be behind some of those health benefits. ...continue reading "Walnuts Feed Beneficial Gut Bacteria and Other Health Benefits"
A wacky study in some ways, but the results give another great reason to eat dark chocolate ("It's for my vision") if the results hold up with more research. Unfortunately the milk chocolate used did not have the same beneficial effects for vision (it just had no effect). But still to be determined is how long does the small increase in vision acuity and contrast sensitivity last after eating dark chocolate, and does it really mean anything in the real world? The beneficial results in vision were found about 2 hours after eating the dark chocolate, so it is unknown how long the beneficial effect lasted.
The good news is that in the study 30 healthy adults were randomly assigned to different groups, it was "double blind" (no one knew who got what to eliminate bias), it was rigorously done, they used real chocolate available to everyone (72% Cacao Dark Chocolate bar vs Crispy Rice Milk Chocolate bar - both from Trader Joe's), and the researchers had no ties to industry. The researchers concluded eating a "dark chocolate bar improves the ability to see low- and high-contrast targets, possibly owing to increased blood flow", but they don't know what this means for real life.
As the researchers point out - there were 8 times more flavanols in the dark (316.3 mg) vs milk chocolate bar (40 mg). Their thinking was clear in the study's introduction: "Several studies suggest that dark chocolate from favanol-rich cacao beans may enhance blood flow to central and peripheral nervous systems, improve cardiovascular function, and retard memory loss and other signs and symptoms of degenerative diseases, including Alzheimer and Parkinson diseases. The cacao flavanols in dark chocolate have antioxidant effects that retard and partially reverse degenerative changes in various diseases. Dark chocolate consumption also has been associated with enhanced mood and cognition." Wow.
The big question: How much dark chocolate did they eat to get these beneficial effects? Answer: 47 grams (or 1 serving, 280 calories) of the 72% cacao dark chocolate. From Medical Xpress:
A bit of dark chocolate might sweeten your vision
It may not replace prescription glasses, but a few bites of dark chocolate might offer a slight and temporary bump up in vision quality, new research suggests. Heart-healthy compounds in chocolate called flavanols appeared to sharpen eyesight for a group of 30 healthy young adults in the new study. The observed change in vision was small, but significant. However, the study authors stressed that it's too early for ophthalmologists to recommend chocolate as medicine for the eyes.
...continue reading "Eating Dark Chocolate Benefits Vision?"
The last post was about several reviews of vitamin D studies, and how when people are put randomly into different groups and then followed for a while - that the studies generally are not finding the same wonderful effects of higher levels of vitamin D in the blood that observational studies are finding - instead finding no effect or mixed results. Some issues with observational studies: the groups are self-selected, some are a one time snapshot of a person (thus one can't tell what happens over time); and can't prove cause and effect (can only say there is an association or link). [See all posts about vitamin D.]
But anyway, today's post is about some more vitamin D studies, all published in 2018. All of them find health benefits from higher blood levels of vitamin D. What is an ideal level of vitamin D varies from study to study, and some are observational - thus can only say "find an association with" in the findings. The fifth study finds beneficial effects from higher doses of vitamin D, and the participants were randomly assigned to the groups (good!). Click on links to read details. All excerpts are from Science Daily:
Vitamin D deficiency linked to greater risk of diabetes
An epidemiological study conducted by researchers at University of California San Diego School of Medicine and Seoul National University suggests that persons deficient in vitamin D may be at much greater risk of developing diabetes. The findings are reported in the April 19, 2018 online issue of PLOS One. ...continue reading "Five Studies Looking at Vitamin D and Health"
The controversy over whether people should be supplementing with vitamin D or not, and whether there are health benefits or harms from vitamin D supplementation is heating up. While observational studies have found health benefits with higher vitamin D blood levels, the beneficial results have generally not held up (or mixed findings) when people were randomly assigned to groups (randomized clinical trials). Most agree that blood levels of under 20 ng per mL is too low, but an issue is what is a desirable blood level? Should healthy people routinely supplement?
Having higher blood levels of vitamin D from sunshine appears to be good (it's the sunshine vitamin, after all). It's the taking of a vitamin D supplement that is now controversial and being debated. By the way, if one decides to take a vitamin D supplement, then the D3 form is desirable (rather than D2).
It was pointed out that a number of negative health effects can occur in those taking more than 4000 IU daily of vitamin D. For example, it may cause toxic effects such as renal impairment, hypercalcemia, or vascular calcification. In 2014, 3% of all U.S. adults and 6.6% of adults older than 60 years reported taking a vitamin D supplement of 4,000 or more IU per day. [See all vitamin D posts - most discuss observational studies finding benefits.]
The following are articles from Medscape (the medical site) and American Family Physician discussing recent research that is not finding health benefits with vitamin D supplementation, or mixed findings (e.g. one review found it may be protective in lowering death from any reason or from cancer; also reduce the number of upper respiratory infections). Therefore, some medical groups suggest that vitamin D screening is an unnecessary test, a waste of money, and shouldn't be routinely done in healthy individuals. Note that many, many trials are going on right now to try to settle the vitamin D supplement issue (whether there are health benefits or not). ...continue reading "Mixed Findings In Vitamin D Supplement Studies"
Does the type of iron in supplements and additives matter for your health? OK, this was a preliminary study and done in a lab using human cells, which means much more research needs to be done, but... It may be that different forms of iron in supplements and additives have slightly different effects in the human body, specifically the intestines. Ferrous sulphate so far looks good (had no effect on the cancer cells studied), while 2 other forms of iron - ferric citrate and ferric EDTA - may actually promote the formation of colon cancer. That is, they may be considered carcinogenic.
Ferric EDTA and ferric citrate have been observed to promote colon cancer in studies using mice. Bottom line: When buying supplements and foods, check labels to make sure the iron is in the form of ferrous sulphate, and not ferric citrate or ferric EDTA. From Science Daily:
Certain iron supplements may influence the development of colon cancer ...continue reading "Perhaps The Type Of Iron Supplement Matters"