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The Big 10

10 facts about vitamin D from research. Why it’s important to know your level.

GrassrootsHealth analysis associated vitamin D with 67% lower cancer risk.

GrassrootsHealth found an inverse association between vitamin D serum levels and all non-skin cancer incidence. The analysis included pooled data from two study cohorts of women aged 55 years and older. Those with vitamin D serum levels ≥ 40 ng/ml, had a 67% lower risk of cancer when compared with those <20 ng/ml.

The Paper

Serum 25-Hydroxyvitamin D Concentrations ≥40 ng/ml are Associated with >65% Lower Cancer Risk: Pooled Analysis of Randomized Trial and Prospective Cohort Study
Sharon L. McDonnell, MPH et al.
April 2016

The Paper

Post-hoc analysis of vitamin D status and reduced risk of preterm birth in two vitamin D pregnancy cohorts compared with South Carolina March of Dimes 2009-2011 rates
Carol Wagner, et al.
Medical University of South Carolina
October 2015

Having a vitamin D level of at least 40 ng/ml may decrease pregnancy comorbidities.

This analysis found that women with vitamin D levels of 40-60 ng/ml have a 46% lower preterm birth rate than the general population (the findings were more robust in Hispanic and Black women). The analysis also showed a 59% lower risk for premature birth by pregnant women who had blood levels of vitamin D (25(OH)D) at or over 40 ng/ml by their third trimester than women who had levels below 20 ng/ml.

You may lower your risk of type 2 diabetes by 60% with a vitamin D level over 40 ng/ml.

For this study on diabetes, the GrassrootsHealth data was compared to data from the National Health and Nutrition Examination Survey (NHANES). The GrassrootsHealth cohort has a median 25(OH)D level of 41 ng/ml vs. NHANES with a median of 22 ng/ml. When comparing the number of cases seen in each population group in the study period, the GrassrootsHealth cohort has a full 60% lower incidence rate of diabetes.

The Paper

Incidence rate of type 2 diabetes is >50% lower in GrassrootsHealth cohort with median serum 25-hydroxyvitamin D of 41 ng/ml than in NHANES cohort with median of 22 ng/ml
Sharon L. McDonnell, MPH et al.
The Journal of Steroid Biochemistry and Molecular Biology
July 2015

The Paper

Letter to Veugelers, P.J. and Ekwaru, J.P., A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D
Robert Heaney, MD et al.
March 2015

9600 IU of vitamin D a day, from all sources, is necessary to get 97.5% of the world up to 40 ng/ml.

The recommended intake of vitamin D specified by the IOM is 600 IU/day through age 70 years, and 800 IU/day for older ages. Calculations by GrassrootsHealth scientists and other researchers have shown that these doses are only about one-tenth those needed to cut incidence of diseases related to vitamin D deficiency. The authors propose a new RDA with a value of approximately 7,000 IU/day from all sources.

A vitamin D level of 40-60 ng/ml may provide a significant reduction in risk for breast cancer.

In a prospective study of 844 female participants aged 60+ years, GrassrootsHealth examined the relationship between serum 25(OH)D and the incidence of breast cancer. Those with concentrations ≥50 ng/ml had an 80% lower risk of breast cancer than those with concentrations <50 ng/ml, adjusting for age and BMI. These findings suggest that 25(OH)D concentrations above 50 ng/ml may provide additional benefit in the prevention of breast cancer.

The Paper

25(OH)D Serum Levels May Provide Additional Reduction in Breast Cancer Risk
Sharon L. McDonnell, MPH et al.
American Society for Nutrition, Scientific Sessions and Annual Meeting
April 2014

The Paper

Quantifying the food sources of basal vitamin D input
Sharon L. McDonnell, MPH et al.
Journal of Steroid Biochemistry and Molecular Biology
November 2013

Eating the right foods can help increase your vitamin D level.

From 780 non-supplement taking, adult, D*action participants who completed a limited questionnaire on dietary intake along with a lifestyle questionnaire, some food sources were found to be associated with vitamin D serum levels: eggs, whole milk cottage cheese, red meat and total protein. 25(OH) D3 rose by about 1 ng/ml for each weekly serving of whole milk cottage cheese (3 oz) and each daily serving of one of the following: eggs (1 egg), red meat (3 oz) and total protein (3 oz).

Other than food, there are many additional ways to get your vitamin D.

Based on this analysis of data provided by D*action participants, non-food factors associated with vitamin D serum levels were indoor tanning use, sun exposure, body mass index (BMI), and percent of work performed outdoors.

The Paper

Quantifying the non-food sources of basal vitamin D input
Sharon L. McDonnell, MPH et al.
Journal of Steroid Biochemistry and Molecular Biology
November 2013

The Paper

25-Hydroxyvitamin D in the Range of 20 to 100 ng/ml and Incidence of Kidney Stones
Stacie Nguyen, MPH et al.
American Journal of Public Health
October 2013

Vitamin D serum levels of 20-100 ng/ml have no association with kidney stones.

The research team used data collected from 2,012 participants enrolled in GRH’s D*action study. Thirteen individuals reported having kidney stones during the study time; occurrences were confirmed by medical records or interview. The study found no statistically significant association between 25(OH)D serum levels and kidney stone risk. In fact, the researchers found a non-significant trend towards lower incidence of kidney stones for those with higher 25(OH)D serum levels.

Study finds the average amount of vitamin D we get per day is 2,000 IU vs. the 300 IU previously taught in medical school.

In this re-analysis, the total basal input (food plus sun) was calculated to range from a low of 778 IU/d in patients with end-stage renal disease to a high of 2667 IU/d in healthy Caucasian adults. The authors conclude that: 1) all-source, basal vitamin D inputs are approximately an order of magnitude higher than can be explained by traditional food sources; 2) cutaneous input accounts for only 10–25% of un-supplemented input at the summer peak; and 3) the remainder must come from undocumented food sources, possibly in part as preformed 25(OH)D.

The Paper

All-Source Basal Vitamin D Inputs are Greater Than Previously Thought and Cutaneous Inputs are Smaller
Robert P. Heaney, MD et al.
The Journal of Nutrition
March 2013

The Paper

Vitamin D Supplement Doses and Serum 25-Hydroxyvitamin D in the Range Associated with Cancer Prevention
Cedric F. Garland, Dr PH FACE, et al.
Anticancer Research

Vitamin D dosing is not the same for everyone. It all starts with knowing your level.

In an analysis of vitamin D serum levels and daily supplemental vitamin D intake amounts for 7,324 D*action participants, we found that while average serum level rises with increased intake, there is a wide range of individual serum levels at any given intake amount. For example, with a supplemental intake of 4000 IU/day, serum levels were observed from 20 ng/ml (50 nmol/L) to 120 ng/ml (300 nmol/L).

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