Vitamin D: Don’t Overdo a Good Thing

September 24th, 2015 by Jack Norris RD

Came across a sensible article on vitamin D supplementation today. Thanks, Jeff!

Vitamin D: Don’t Overdo a Good Thing by Tod Cooperman, M.D.

Excerpt:

“It seems that initial reports led some experts to ignore the recommendation of the National Academies’ Institute of Medicine, which says that only people with vitamin D levels under 20 ng/mL are deficient. Instead, these experts argued that people need to maintain levels which are at least 50 percent higher–30 ng/mL….Further feeding this frenzy have been clinical laboratories — which profit from more vitamin D tests. When you get a vitamin D test back, the “normal” range shown next to your result often extends up to 100 ng/mL (which is actually far beyond the normal range), leading people with levels in the 20s, for example, to believe they needed more vitamin D.”

Taiwanese Vegans: Doing Well!

September 17th, 2015 by Jack Norris RD

A study from Taiwan shows differences between vegans, lacto-ovo vegetarians, and omnivores (1).

I’m only going to report the findings for vegans, but the study abstract lists the findings for lacto-ovo vegetarians if you’re interested.

At baseline, vegans had lower rates of abnormally high waist circumference, body mass index, blood pressure, blood glucose, total cholesterol, and LDL cholesterol. Vegans had a higher rate of abnormally low HDL cholesterol, but a lower rate of abnormally high total to HDL cholesterol ratio (which is more important than absolute HDL levels). Theses finding are all very similar to what’s been found in Western vegans.

Subjects were followed for an average of 2 years. The one statistically significant finding during follow-up for vegans was that each additional year of a vegan diet lowered the risk of obesity by 7%.

Other items of note are that the lower rates of high blood pressure could be explained by lower body mass index and that vegans ate the smallest amount of fried foods of any diet group.

In conclusion, Taiwanese vegans have better metabolic markers than omnivores.

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References

1. Chiu YF, Hsu CC, Chiu TH, Lee CY, Liu TT, Tsao CK, Chuang SC, Hsiung CA. Cross-sectional and longitudinal comparisons of metabolic profiles between vegetarian and non-vegetarian subjects: a matched cohort study. Br J Nutr. 2015 Sep 10:1-8. [Epub ahead of print] | link

New Report on Vegetarians and Colorectal Cancer

September 3rd, 2015 by Jack Norris RD

I have updated the VeganHealth.org article Cancer, Vegetarianism, and Diet with results from the Netherlands Cohort Study-Meat Investigation Cohort (1).

The study found that vegetarians had a non-statistically significant, reduced risk for colorectal cancer. In comparison to non-vegetarians, the rate for vegetarians was .78 (.51, 1.20) when adjusted for age and gender, and .89 (.58, 1.39) when further adjusted for energy, smoking, alcohol, body mass index, physical activity, and education.

It follows a long line of research that has mostly found non-significant differences between vegetarians and non-vegetarians for colorectal cancer (see Table 3).

Some other interesting findings from the report:

– Fiber and soy product intake contributed most to the observed inverse risk.

– People who ate meat only once a week had a borderline statistically lower risk (.72, .52-1.00) than those eating meat 6-7 days per week in the model adjusting only for age and gender. Adjusting for the remaining variables (mentioned above) weakened the association.

– Substituting 5% of energy from meat protein with 5% of energy from dairy protein was associated with a 24% reduced risk of colorectal cancer, after adjustment for confounding variables (P=0.055). Dairy products may protect against colorectal cancer risk due to their high calcium content.

This is only a very small piece of the puzzle on diet, meat, dairy, vegetarianism and colorectal cancer, but it underlines the recommendations that vegans make sure they’re getting enough calcium.

In summary, there is some good news here, but it suggests that vegans get enough calcium.

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1. Gilsing AM, Schouten LJ, Goldbohm RA, Dagnelie PC, van den Brandt PA, Weijenberg MP. Vegetarianism, low meat consumption and the risk of colorectal cancer in a population based cohort study. Sci Rep. 2015 Aug 28;5:13484. | link | PDF Available

Omega-3 Supplements Fail to Slow Cognitive Decline

September 3rd, 2015 by Jack Norris RD

A reader asked me to comment on the study, Effect of Omega-3 Fatty Acids, Lutein/Zeaxanthin, or Other Nutrient Supplementation on Cognitive Function (1). It is a recent study that got some attention for showing that omega-3 supplements failed to prevent cognitive decline in older people.

I contacted the authors to get the blood levels of EPA and DHA at baseline to compare them to typical levels in non-supplementing vegans. Unfortunately, they didn’t measure them in a way that allowed for me to compare to studies on vegans. If they had been similar to typical levels in vegans we would have some evidence that the lower levels in vegans are not a problem, but since I couldn’t tell, I don’t consider it to provide any evidence that vegans cannot benefit from omega-3 supplements.

The good news is that this report could help reduce the use of fish oil supplements by non-vegetarians.

For more on this issue, see Omega-3 Fatty Acid Recommendations for Vegetarians.

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References

1. Chew EY, Clemons TE, Agrón E, Launer LJ, Grodstein F, Bernstein PS; Age-Related Eye Disease Study 2 (AREDS2) Research Group. Effect of Omega-3 Fatty Acids, Lutein/Zeaxanthin, or Other Nutrient Supplementation on Cognitive Function: The AREDS2 Randomized Clinical Trial. JAMA. 2015 Aug 25;314(8):791-801. | link

Latest From Dr. Greger

September 3rd, 2015 by Jack Norris RD

Dr. Michael Greger of NutritionFacts.org recently released his DVD Latest in Clinical Nutrition Volume 26: Volume 26 – Dr. Greger Takes on Smoothies.

Dr. G has also released his 2015 Live Year-in-Review Presentation streaming for free. In it he presents a very interesting history of the medical profession’s promotion of cigarette smoking and compares it to the promotion of meat-eating.

Check ’em out!

Absorption of Various Forms of B12

August 13th, 2015 by Jack Norris RD

Breaking news from 1971 for vitamin B12 junkies!

A reader alerted me to a 1971 study comparing absorption rates of cyanocobalamin, hydroxocobalamin, methylcobalamin, and adenosylcobalamin (1).

They found that at doses of 1 µg, 5 µg, and 25 µg, all forms were absorbed at about the same rate for practical purposes.

However, the researches suggested, based on other research, that at higher doses, cyanocobalamin is better absorbed. They theorized that this could be because absorption of methylcobalamin by way of intrinsic factor is efficient while cyanocobalamin is better absorbed through passive diffusion.

Based on this study, I’ve cleaned up the VeganHealth.org page Methylcobalamin & Adenosylcobalamin where you can also see a table of the absorption rates from this 1971 study.

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References

1. Adams JF, Ross SK, Mervyn L, Boddy K, King P. Absorption of cyanocobalamin, coenzyme B 12 , methylcobalamin, and hydroxocobalamin at different dose levels. Scand J Gastroenterol. 1971;6(3):249-52. | link

Pre-Type 2 Diabetes and Lean Vegans

August 9th, 2015 by Jack Norris RD

Just added this article to VeganHealth.org:

Preface

by Jack Norris

Recently, I have been contacted by a small group of lean, pre-diabetic vegans. I had never heard of thin vegans developing pre-diabetes; it turns out that it’s not uncommon for lean people to develop pre-type-2 diabetes.

Here is an article by Susan Papuga, one of the people who contacted me, who has researched the topic thoroughly. If you aren’t familiar with the normal references for the numbers discussed below, please see Diabetes: Tests and Diagnosis from Mayo Clinic.

Pre-Type 2 Diabetes and Lean Vegans

by Susan Papuga

The majority of people with type 2 diabetes are overweight and suffer from hyperglycemia (high blood sugar) due to insulin resistance. However, there is also a condition in which thin people suffer from hyperglycemia. Few studies have been done on lean diabetics and are primarily on Asian populations. Many of these studies have found that lean type-2 diabetics are suffering from a deficiency of the insulin-producing beta cells rather than from insulin resistance. An even smaller subset rarely mentioned are lean vegans with high blood glucose; further research is needed to determine the cause of their pre-diabetes or diabetes.

The International Diabetes Foundation has developed a document, Guideline for Management of Postmeal Glucose (PDF), which states, “Although control of fasting hyperglycaemia is necessary, it is usually insufficient to obtain optimal glycaemic control. A growing body of evidence suggests that reducing postmeal plasma glucose excursions is as important, or perhaps more important for achieving HbA1c goals.” Their recommendation is that two-hour postmeal (also known as postprandial) plasma glucose should not exceed 140 mg/dl (7.8 mmol/l) as long as hypoglycemia is avoided.

In order to meet that goal for a lean vegan who is pre-diabetic or diabetic, careful consideration needs to be paid to diet. One challenge is how to prevent postprandial spikes while reducing carbohydrate and still maintaining adequate body weight. The Eco-Atkins diet can be an effective path to follow with higher fat and protein consumption from nuts, seeds, avocados, soy foods, and seitan–all helping to provide needed calories. Carbohydrate should be chosen wisely, emphasizing high fiber and low glycemic foods.

The Guideline further states, “Self-monitoring of blood glucose should be considered because it is currently the most practical method for monitoring postmeal glycaemia.” For a lean vegan, this is an important step in taming impaired glucose metabolism. For a few in our group of lean vegans, our fasting glucose was only slightly elevated while an HbA1c test and/or postprandial glucose identified pre-diabetes.

My first indication of impaired glucose metabolism was during a routine lab which showed a slightly elevated fasting glucose of 101. I started testing my fasting and postmeal glucose at home and mentioned to my doctor that I was seeing some high numbers for postmeal, up to 185. A person with normal glucose metabolism rarely goes over 140 postprandial. An oral glucose tolerance test confirmed a pre-diabetes diagnosis, and then began my journey to find a way to lower those numbers while eating a healthy vegan diet.

Personally, I’ve had success at keeping my fasting glucose under 100 mg/dl and postprandial glucose under 140 mg/dl with a diet similar to Eco-Atkins. I found that the processed grains in breads and pasta and many mid- to high-glycemic index foods, even in modest amounts, will cause a high postprandial spike. To keep glucose low and slow, the high fiber carbohydrate are best. I’ve stopped eating dried fruit and eat low glycemic index fresh fruit only in small servings; instead, I fill up with hull-less barley (1), soybeans, legumes, chia seeds, wheat bran, non-starchy vegetables, nuts, seeds, avocado, and seitan.

Tracking daily nutrients on Cronometer.com has been invaluable for meeting the RDA targets. Consequently, my lab results are coming back with great numbers: low cholesterol (high HDL), low inflammation, low blood pressure, normal glucose, and HbA1c at 5.0. This diet works well for me and the other vegans in our group. We’ll continue to monitor our glucose and labs, adjusting when needed, but overall we are quite pleased, as are our doctors, with the outcomes.

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Footnotes

1. Barley can be hulled or hull less. Hull less barley has a lower glycemic index and higher nutrient profile.

Latest in Clinical Nutrition: Volume 25 Now Available

June 24th, 2015 by Jack Norris RD

Dr. Michael Greger of NutritionFacts.org has released Volume 25 of his Latest in Clinical Nutrition DVD series. This one has a strong focus on digestive ailments. Dr. Greger scours the earth for important studies in peer-reviewed journals…so you don’t have to!

You can order Volume 25 by clicking here.

Gluten Sensitivity: Hard to Self-Diagnose

June 24th, 2015 by Jack Norris RD

A 2015 study from Italy found that among people attending a gastroenterology clinic complaining of gluten-related symptoms, few actually improved after six months on a gluten-free diet (1).

A total of 392 patients reported gluten-related symptoms upon an appointment at the clinic. Among them, celiac disease was confirmed in 26 and a wheat allergy was confirmed in 2. The remaining 364 were advised to follow–and apparently complied–with a gluten-free diet. After six months, only 27 were symptom-free. The researchers concluded that 86% of people who think they suffer from gluten-related symptoms actually do not.

Thank you, Joseph Gonzales, RD.

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References

1. Capannolo A, Viscido A, Barkad MA, Valerii G, Ciccone F, Melideo D, Frieri G, Latella G. Non-Celiac Gluten Sensitivity among Patients Perceiving Gluten-Related Symptoms. Digestion. 2015 May 30;92(1):8-13. | link

Vitamin D3 Performs Slightly Better Than D2 in Clinical Trial

June 23rd, 2015 by Jack Norris RD

I have updated the VeganHealth.org article, Calcium and Vitamin D, with a synopsis of the following clinical trial:

“A 2013 study from Germany found that with supplementing daily for 8 weeks at about 2,000 IU, D3 was more effective at raising vitamin D levels (1). The average 25(OH)D levels increased 46 nmol/l in the D3 group (for an average of 89 nmol/l) but only 30 nmol/l in the D2 group (for an average of 68 nmol/l). Vitamin D2 supplementation appeared to decrease the amount of circulating vitamin D3. PTH levels were not different between groups. Because D2 raised levels into the recommended range (50 – 125 nmol/l), it seems preliminary to assume that D3 is more healthy based on these results, though evidence is mounting that D3, even at smaller doses, can raise vitamin D levels higher or more quickly than D2.”

I don’t think this has any health implications for most vegans. If you have experienced a stubborn vitamin D deficiency, it adds some credence to the idea that you should try vitamin D3. Vegan vitamin D3 is available.

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References

1. Lehmann U, Hirche F, Stangl GI, Hinz K, Westphal S, Dierkes J. Bioavailability of vitamin D(2) and D(3) in healthy volunteers, a randomized placebo-controlled trial. J Clin Endocrinol Metab. 2013 Nov;98(11):4339-45. doi: 10.1210/jc.2012-4287. Epub 2013 Sep 3. | link