Vitamin D and the prevention of Child-onset Type I Diabetes

Matteo Tino, B. Kin, PTS, CSCS

Vitamin D is prevalent in a limited number of foods such as fatty fish (i.e. Salmon), egg yolks and milk. It is important in the regulation of phosphorus and calcium in the blood. (DeLuca, 1993) Vitamin D is also produced in the skin by UVB radiation (sunlight). However, most milk is not fortified with enough Vitamin D to act as an appropriate supplement, and most North Americans do not receive enough sunlight to meet their daily vitamin D requirements. (Zella, McCary, & DeLuca, 2003). Ideal consumption of vitamin D is about 20µg (µg=micrograms) or 800IU (UI=International Units) per day; although, this number may be too low. (Veith, 2004) In the absence of sunlight at least 25µg (1000 IU) of Vitamin D is required. (Veith, 2004) Vitamin D deficiency has already been associated with rickets and vitamin D is effective in the prevention of osteoporosis, heart disease and some cancers. (Holick, 2004) Recent research has begun to show a correlation between vitamin D consumption and a decreased risk of type 1 (insulin-dependent) diabetes. Diabetes is a major cause of blindness, amputation and death in North America; and between the years 1995-2025 there will be a 35% increase in the world prevalence of diabetes. (King, Aubert & Herman, 1998) As well, there is epidemiological research that shows a relationship between a lack of sun exposure and the risk of diabetes. (Dahlquist & Mustonen, 1994)
According to three separate studies (see Research Review below) a relationship exists between vitamin D consumption and the prevention of type I diabetes. Vitamin D consumption and supplementation is an effective way to prevent the onset of type 1 diabetes. More specifically, a daily 50µg (2000IU) dose of vitamin D greatly reduces the risk of type 1 diabetes in children; and vitamin D supplementation is effective in preventing type 1 diabetes, especially in the absence of appropriate UVB radiation.
Although there are obvious health benefits to the consumption of Vitamin D, there may also be many health risks associated with the over-consumption of vitamin D. Vitamin D “supplementation is only beneficial and safe when the person’s biological concentration of the vitamin is less than optimal.” (Hypponen, Laara, Reunanen, Jarvelin & Virtane, 2001) The Upper Limit (UL) is the maximum amount of a nutrient that a majority of the population can consume before there are health risks. The UL for Vitamin D is 50µg (2000IU) per day (Munro, 2001). However, according to one study, 78% of children who consumed at least 2000IU of Vitamin D had a reduced risk of Type 1 Diabetes. (Hypponen, Laara, Reunanen, Jarvelin & Virtane, 2001). Regardless, Vitamin D supplementation is not effective if it leads to other diseases due to over-supplementation. Also, the relationship between vitamin D consumption, calcium absorption and diabetes should be examined. The benefits of vitamin D consumption may be due to the increased absorbance of calcium. As well, there are many associated risks with exposure to UVB radiation. Sunlight is effective in producing vitamin D in the skin, however increased unprotected exposure to the sun may lead to sun stroke, dehydration, burning and, in some cases, cancers.
Although vitamin D supplementation is effecting in warding off type 1 diabetes, other factors such as diet, body composition and activity level need to be considered. Parents need to be conscious of what their children are eating and how active their children are. An inactive child with poor eating habits is still at risk of developing diabetes regardless of vitamin D supplementation.




Research Review

Intake of Vitamin D and the risks of type 1 diabetes: A birth-cohort study
Hypponen, E., Laara, E,. Reunanen, A., Jarvelin, M.R. & Virtane, S.M.

This study examined the possible relationship between early childhood vitamin D consumption and the risk of type 1 diabetes. The experimenters expected to see a negative relationship between the consumption of vitamin D and the prevalence of type 1 diabetes. A total of 10 821 children participated in the study. Children who regularly supplemented for vitamin D had an 88% decrease in Type 1 diabetes risk when compared to children who did not supplement for vitamin D. Children that consumed 50µg (2000IU), the recommended daily dose of vitamin D, had a 78% reduction in type 1 diabetes risk than children who received a lower dosage. Essentially, consuming 2000IU of vitamin D daily in the first year of life lowers the risk of type 1 diabetes.

Vitamin D supplement in early childhood and risks for type 1 (insulin-dependent) diabetes mellitus
The EURODIAB Substudy 2 Study Group

The aim of this study is to determine whether there is a relationship between early childhood vitamin D consumption and the risk of type 1 diabetes for several populations across Europe. The authors hypothesized that “non-genetic risk factors which can trigger the events subsequently leading to childhood-onset diabetes are operating early in life”, and that vitamin D supplementation is effective in the prevention of type 1 diabetes. The study concludes that vitamin D supplementation leads to a decreased risk of child-onset type 1 diabetes.

Oral administration of 1,25-dihydroxyvitamin D3 completely protects NOD mice from insulin-dependent diabetes mellitus
Zella, J.B., McCary, L.C. & DeLuca, H.F.

The aim of this experiment was to determine the effectiveness of vitamin D in the prevention of type 1 diabetes in non-obese diabetic mice. The experimenters hypothesized that vitamin D supplementation from UV radiation and oral supplementation will protect the mice from type 1 diabetes. 65% of vitamin D deficient mice who received no vitamin D supplementation were diabetic compared to only 26% of vitamin D sufficient mice who only received UV radiation. In addition, vitamin D deficient mice had an earlier onset of diabetes than the vitamin D sufficient mice. Mice that received a daily 50ng oral supplement of vitamin D had no incidence of type 1 diabetes, whether they received UV radiation or not. This study shows the strong relationship between vitamin D supplementation and the decreased risk of type 1 diabetes, especially in the absence of UVB radiation.

References

Dahlquist, G. & Mustonen, L. (1994). Childhood onset diabetes - time trends an
climatological factors. International Journal Epidemiology, 23, 1239-1241

DeLuca, H.F. (1993). Vitamin D: 1993. Nutrition Today, 28, 6-11.

Holick, M.F. (2004). Vitamin D: importance in the prevention of cancers, type 1 diabetes,
heart disease, and osteoporosis. American Journal of Clinical Nutrition, 79, 362-371.

Hypponen, E., Laara, E,. Reunanen, A., Jarvelin, M.R. & Virtane, S.M. (2001). Intake of
vitamin D and risk of type 1 diabetes: A birth-cohort study. The Lancet, 358, 1500-1503.

King, H., Aubert, R.E. & Herman, W.H. (1998). Global burden of diabetes, 1995-2025:
Prevalence, numerical estimates, and projections. Diabetes Car, 21(9), 1414-1431.

Munro, I. (2001). Derivation of tolerable upper intake levels of nutrients. American
Journal of Clinical Nutrition, 74, 865-867.

The EURODIAB Substudy 2 Study Group. (1999).Vitamin D supplement in early
childhood and risk for type I (insulin-dependent) diabetes mellitus. Diabetologia,
42, 51-54.

Vieth, R.(2004). Why the optimal requirement for Vitamin D3 is probably much
higher than what is officially recommended for adults. Journal of Steroid Biochemistry & Molecular Biology 89–90, 575–579

Zella, J.B., McCary, L.C. & DeLuca, H.F. (2003). Oral administration of 1,25-
dihydroxyvitamin D3 completely protects NOD mice from insulin-dependent diabetes mellitus. Archives of Biochemistry and Biophysics, 417, 77–80