Do nuts really help with diabetes and cardiovascular disease?

Posted on May 8, 2010 by Dr. Jonathan

The authors of this paper published in the British Journal of Nutrition begin by observing…

“The ability of nuts to improve the blood lipid profile and reduce the risk of CHD (coronary heart disease) is now well established. The interest that health effects of nuts have gained recently has brought the possible benefits of consuming nuts, such as improvement in the conditions of the metabolic syndrome, and their potential to prevent and control diabetes into focus.”

They report an important observation:

“Acute feeding studies indicate that nuts have minimal effects on rising postprandial blood glucose levels when eaten alone, and diminish the postprandial glycaemic response when consumed with high-glycaemic index carbohydrate foods in both normoglycaemic and type 2 diabetic individuals.”

This means that whether your blood sugar is still OK or has already gone too high, if you consume nuts with a meal or snack—even if it is, at least to a degree, more glycemic than desirable—the nuts will prevent your blood sugar from spiking too high and overstimulating the release of insulin. And eating nuts alone has a trivial effect on raising blood sugar.

The authors further note…

“Nuts have a healthy nutritional profile, high in MUFA (monounsaturated fatty acids) and PUFA (polyunsaturated fatty acids), are a good source of vegetable protein and are rich in fibre, vitamins and minerals….early data indicate that the inclusion of nuts in the diets of individuals with diabetes and the metabolic syndrome is warranted, in view of their potential to reduce CHD risk.”

However, don’t forget that tree nuts are among the more common food allergens.

Sugars raise bad fats in the blood

Posted on May 4, 2010 by Dr. Jonathan

JAMA Readers and patients here know how higher levels of insulin from a high glycemic diet can result in an increase in the harmful kinds of fat in the blood. It will come as no surprise that a paper just published in the Journal of the American Medical Association adds more evidence to the association. The the objective of the authors was to…

“…assess the association between consumption of added sugars and blood lipid levels in US adults.”

They analyzed the data for 6,113 adults collected over seven years for sugars in the diet and levels of HDL and LDL cholesterol and triglycerides. A clear correlation between higher levels of sugars and lower HDL (“good” cholesterol), higher LDL (“bad” cholesterol) and higher triglycerides emerged. There was strong evidence for maintaining a low glycemic diet to regulate cholesterol:

“Among higher consumers (≥10% added sugars) the odds of low HDL-C levels were 50% to more than 300% greater compared with the reference group (<5% added sugars).”

Their conclusion was mildly stated:

“In this study, there was a statistically significant correlation between dietary added sugars and blood lipid levels among US adults.”

Have you been trying but not succeeding in getting cholesterol and/or triglycerides down with a low fat diet? There has been so much science done on the correlation between insulin sensitivity and cholesterol levels; it’s surprising this wasn’t noted by the authors. Just one example is a fresh paper in the Journal of Lipid Research that begins with the well-known fact:

“Cholesterol synthesis is upregulated and absorption downregulated in insulin resistance and in type 2 diabetes.”

Interestingly, the authors wanted to see if any level of insulin resistance would have an effect on cholesterol synthesis:

“We investigated whether alterations in cholesterol metabolism are observed across the glucose tolerance status, from normoglycemia through impaired glucose tolerance to type 2 diabetes…”

What conclusions did they draw from their data?

“In conclusion, cholesterol metabolism was altered already in subjects with impaired fasting glucose. Upregulated cholesterol synthesis was associated with peripheral insulin resistance independent of obesity.”

How to eat healthy fat and oil is another topic, but if cholesterol and triglycerides are the issue—pay attention to sugars and insulin.

Mercury levels found to be higher in restaurant sushi tuna than supermarket

Posted on April 23, 2010 by Dr. Jonathan

An innovative and alarming study was just published in the journal Biology Letters that not only confirms the high level of toxicity of certain tuna species and uses DNA ‘barcode’ technology to reveal that the type of tuna in most restaurant sushi is the most contaminated with mercury.

The authors remind us:

“Excessive ingestion of mercury—a health hazard associated with consuming predatory fishes—damages neurological, sensory-motor and cardiovascular functioning.”

It can be difficult to identify a specific tuna species and know where it came from using conventional methods. This is where DNA barcodes advances the science:

“Accurate identification of commercial fish species has many public health and legal applications. DNA barcodes—short nucleotide sequences used to identify species—can serve as an important tool allowing regulatory agencies to recognize ambiguous food items that are fraudulent or hazardous.”

The authors undertook an extensive study to match confirmed identity with mercury content:

“We tested the mercury content of 100 tuna sushi samples from 54 restaurants and 15 supermarkets collected from October 2007 to December 2009 in New York, New Jersey, and Colorado.”

What did they find?

“The mean mercury concentrations of all samples exceed the concentration permitted by Japan, and the maximum daily consumption considered safe by the US Environmental Protection Agency. Mean mercury levels for bluefin akami exceed those permitted by the US Food and Drug Administration, Health Canada and the European Commission.On average, one order of Bigeye Tuna sushi—the species used most often for sushi—exceeds the safe maximum daily dose recommended by Health Canada and the safe limit established by the World Health Organization and FAO for women of childbearing age.”

Moreover…

“Because the mercury concentrations found in our sushi were significantly higher than levels documented by the Food and Drug Administration this could reflect that our samples came from larger fish (the FDA lacks bluefin data). We found significantly lower mercury levels in supermarket sushi because samples were dominated by Yellowfin Tuna, which comprised a minority of restaurant samples and was found to be the species with the lowest mercury concentration.”

Science Now At this time health agencies are not using these findings that place Bigeye and bluefin tuna in the category that the FDA and EPA advise should be totally avoided by pregnant or nursing women and children. You may also like to read a report on this study published in Science Now by the American Academy of Sciences. How do you find out if mercury is a problem for you? Not by provoked chelation (see the earlier post), and inquire about or ‘stay tuned’ for posts on porphyrin profiles, anti-mercury antibodies and MELISA test technology.

Can chili peppers help gastritis?

Posted on April 18, 2010 by Dr. Jonathan

First of all, isn’t it interesting that there is so much science being done that there is a journal called Helicobacter devoted to research on the bacteria Helicobacter pylorii? Most of you will recognize it as the pathogen associated with gastric ulcers and gastritis (stomach inflammation). A study published there investigated the effect of capsaicin (the chemical that makes chilies hot) on the stomach lining when there is inflammation due to Helicobacter infection.

“Capsaicin, the main pungent ingredient of hot red and chili pepper, has been considered as not only a cytoprotective [cell protector] but also a detrimental agent to the gastric mucosa. However, the effect and mechanism of capsaicin that modulate the induction of pro-inflammatory cytokine in Helicobacter pylori-infected epithelial cells have not been investigated previously.”

The authors exposed gastric cells with various concentrations of capsaicin. Their data showed that even a very low dose of capsaicin reduced inflammation by inhibiting H. pylori-induced IL-8 and NF-κB inflammatory pathways, leading to this conclusion:

“Nontoxic dose of capsaicin inhibited H. pylori-induced IL-8 production by gastric epithelial cells through the modulation of IκB-, NF-κB-, and IL-8 pathways. We conclude that capsaicin can be proposed as a potential anti-inflammatory drug by inhibition of the production of IL-8 in H. pylori-infected gastric epithelium.”

This doesn’t mean that you don’t need to fully get rid of the Helicobacter infection. We can diagnose it much more accurately than in the past with advanced DNA amplification technology. But a little warmth in your food might help reduce the inflammation meanwhile.

Is grass-fed beef more nutritious?

Posted on March 22, 2010 by Dr. Jonathan

Like us, cattle have a very different metabolic response to eating lots of green vegetables (grass in this case) versus grains. This paper recently published in the Nutrition Journal reviews research performed over the last thirty years:

“Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability.”

Personally, I much prefer the taste of grass-fed beef as do others I know. They detail some of the differences:

“Grass-based diets have been shown to enhance total conjugated linoleic acid isomers…and omega-3 FAs (fatty acids)on a g/g fat basis…grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA and less cholesterol-elevating SFAs such as myristic and palmitic FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione and superoxide dismutase activity as compared to grain-fed contemporaries…”

They alert consumers to the different color grass-fed beef may have due to a higher carotenoid (vitamin A precursor) content as well as different cooking characteristics. They don’t, however, note in their paper how much more humane a BioMed Central grass-fed lifestyle is compared to grain-fed factory farming. By the way, how do you think studies on an association between red meat and various cancers might have turned out if only organic grass-fed beef was used…?

Two new studies again show benefits of coffee

Posted on February 27, 2010 by Dr. Jonathan

Coffee is in the science news again, with two interesting papers that document its benefits. Both were recently published in the American Journal of Clinical Nutrition. The first paper adds more evidence that drinking coffee reduces the risk of type 2 diabetes. The study involved 69,532 French women who were observed over an 11 year period. The authors report an “inverse association [diabetes]…for both regular and decaffeinated coffee and for filtered and black coffee, with no effect of sweetening. Total caffeine intake was also associated with a statistically significantly lower risk of diabetes. Neither tea nor chicory consumption was associated with diabetes risk.” Interestingly, the authors also noted that the observed benefit was particularly pronounced with coffee consumed at lunch. Their conclusion: “Our data support an inverse association between coffee consumption and diabetes and suggest that the time of drinking coffee plays a distinct role in glucose metabolism.”

Considering the importance of inflammation in chronic disease, the second paper is especially interesting in that it documents reductions in subclinical inflammation and oxidative stress as mechanisms by which coffee lowers the risk of type 2 diabetes. Noting that “Coffee consumption is associated with a decreased risk of type 2 diabetes,” the authors state that their “aim was to investigate the effects of daily coffee consumption on biomarkers of coffee intake, subclinical inflammation, oxidative stress, glucose, and lipid metabolism.” They observed a number of interesting effects, including beneficial lowering of the LDL/HDL ratio and IL-18, and an increase in adiponectin. Meanwhile, no adverse changes were seen on the oral glucose tolerance test. They conclude: “Coffee consumption appears to have beneficial effects on subclinical inflammation and HDL cholesterol, whereas no [adverse] changes in glucose metabolism were found in our study.”

Champagne helps open up blood vessels for heart protection

Posted on December 31, 2009 by Dr. Jonathan

In time for New Year’s eve, an interesting study was recently published in the British Journal of Nutrition that investigated the effects of champagne on blood vessel function. “In order to assess whether acute and moderate Champagne wine consumption is capable of modulating vascular function, we performed a randomised, placebo-controlled, cross-over intervention trial.” The authors stated in their findings that “consumption of Champagne wine, but not a control matched for alcohol, carbohydrate and fruit-derived acid content, induced an acute change in endothelium-independent vasodilatation at 4 and 8 h post-consumption.” (Vasodilation = blood vessel opening.) They also observed “a significant decrease in plasma levels of oxidising species,” and conclude: “Our data suggest that a daily moderate consumption of Champagne wine may improve vascular performance…” Best wishes for the new year!

Coffee and tea reduce risk of type 2 diabetes

Posted on December 26, 2009 by Dr. Jonathan

This paper published in the journal Diabetologia may contradict some assumptions. The investigators set out to “examine the association of consumption of coffee and tea, separately and in total, with risk of type 2 diabetes and which factors mediate these relations.” Their findings may be a surprise to some: “Total daily consumption of at least three cups of coffee and/or tea reduced the risk of type 2 diabetes by approximately 42%.” They go on to conclude: “Drinking coffee or tea is associated with a lowered risk of type 2 diabetes, which cannot be explained by magnesium, potassium, caffeine or blood pressure effects. Total consumption of at least three cups of coffee or tea per day may lower the risk of type 2 diabetes.” How can this be? There are compounds in both beverages that have anti-inflammatory and other beneficial effects. As you know, chronic inflammation plays an important role in type 2 diabetes. HOWEVER: bear in mind that caffeine can aggravate Th2-type autoimmune conditions, and it may be poorly tolerated by those with sympathetic nervous system hyperarousal.

Sensible weight-loss advice in Glamour magazine? Who would have thought…

Posted on December 25, 2009 by Dr. Jonathan

OMG! This departs from my usual posts on publications in the peer-reviewed scientific literature, but it is so rare for me to see something I can recommend in a lay publication that I couldn’t pass it up for the holiday season when it was pointed out by a follower. This article describes the eating plan of Padma Lakshmi, host of the television show Top Chef. It is refreshingly sane. Happy holidays!

Coffee reduces inflammatory reaction to high fat diets

Posted on December 22, 2009 by Dr. Jonathan

Inflammatory cytokines are messenger molecules of the immune system that activate and direct inflammation. The authors of this recently published study state: “In order to investigate the risk-reducing effects of coffee in metabolic syndrome, we performed a study in mice fed a high-fat diet with added coffee and analyzed gene expression in liver and adipose tissues using cDNA microarray.” Metabolic syndrome is also known as ‘pre-diabetes’. The instant coffee significantly reduced inflammatory gene expression, and “Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) [liver enzymes] levels were significantly lower…” Mesenteric (visceral) fat was lower in the decaf group and even lower in the regular coffee subjects. They conclude: “The induction of these anti-inflammatory responses by coffee consumption may contribute to reducing the risks of metabolic syndrome.” HOWEVER, please bear in mind the precautions in the previous post on coffee and tea.