[1] Neurobehav Res Inc, Honolulu, HI 96814 USA
[2] Univ Stellenbosch, Div Human Nutr, ZA-7600 Stellenbosch, South Africa
[3] Univ Cape Town, Div Human Nutr, ZA-7700 Rondebosch, South Africa
[4] Univ Stellenbosch, Dept Stat & Actuarial Sci, ZA-7600 Stellenbosch, South Africa
[5] Univ Stellenbosch, Dept Psychiat, ZA-7600 Stellenbosch, South Africa