Omega-3 fatty acids and vitamin D in traditionally living east-African populations. Lessons from evolution for a healthy lifestyle

PhD ceremony: Ms. M.F. Luxwolda, 16.15 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Omega-3 fatty acids and vitamin D in traditionally living east-African populations. Lessons from evolution for a healthy lifestyle

Promotor(s): prof. F.A.J. Muskiet

Faculty: Medical Sciences

Current dietary recommendations are “Evidence Based.” They derive from research conducted in Western populations. This thesis highlights the subjectivity of these recommendations for two nutrients: the fish oil fatty acid DHA and vitamin D. We investigated African tribes in Tanzania, with lifestyles similar to those of our Paleolithic ancestors (2.5 million to 10.000 years ago). The mostly traditionally living populations that we investigated do not suffer from the typical Western diseases of affluence. It appears that their DHA and vitamin D levels were much higher than currently recommended in Western countries.

A high DHA level is associated with a low risk of psychiatric and cardiovascular diseases. A high milk-DHA might have beneficial effects on the neurological development of the newborn. The current recommendation for DHA intake in Western adults is 250-450 mg/day. Infant formula should contain 0.2-0.4 g% DHA. Tanzanian lactating women with daily fish intakes have a DHA of 8 g% and a milk-DHA of 1.0 g%. A low vitamin D [25(OH)D] is associated with many diseases of affluence. The current recommendation for 25(OH)D by the Dutch Health Council is ³ 30 nmol/L (<70 years) and ³ 50 nmol/L ( ³ 70 years). The mean 25(OH)D in healthy Dutch adults is 60 nmol/L. However, in the Tanzanian tribes we found 115 nmol/L, which increased with 25-60% during pregnancy. Due to the currently reigning, reductionist paradigm of “Evidence Based Nutrition” with single nutrients, we seriously question the way in which current dietary recommendations are developed.