Two conflicting studies... potentially has to do with ratio of PUFA/SFA rather than total PUFA intake.Testosterone, sex hormone-binding globulin, calculated free testosterone, and oestradiol in male vegans and omnivores
Timothy J. A. Key, Liane Roe, Margaret Thorogood, John W. Moore, Graham M. G. Clark and Dennis Y. Wang
British Journal of Nutrition (1990), 64 : 111-119
In a subset of eighteen vegans and twenty-two omnivores for whom 4 d diet recordsTestosterone and cortisol in relationship to dietary nutrients and resistance exercise
were available, there were statistically significant correlations between T and polyunsaturated fatty acids
( r 0.37), SHBG and fat ( r 0.43 f or total fat, 0.46 f or saturated fatty acids and 0.33 f or polyunsaturated
fatty acids), and SHBG and alcohol ( r-0.39). It is concluded that a vegan diet causes a substantial
increase in SHBG but has little effect on total or free T or on E2
The relationships between the hormonal variables and these dietary variables were
examined by calculating partial correlation coefficients, adjusted for age, B MI and dietary
group (vegan or omnivore) (Table 5). Total T was significantly positively correlated with
polyunsaturated fat intake.
Jeff S. Volek, William J. Kraemer, Jill A. Bush, Thomas Incledon and Mark Boetes
J Appl Physiol 82:49-54, 1997.
Preexercise T was signiﬁcantly positively correlatedwith percent energy fat, SFA (g · 1,000 kcal21 · day21 ),and MUFA (g · 1,000 kcal21 · day21 ) and was signiﬁcantly negatively correlated with the percent energy protein, the PUFA/SFA ratio, and the protein-to-carbohydrate ratio (Fig. 2). There were no signiﬁcant correlations observed between any nutritional variables and preexercise C or the absolute increase in T and C after exercise.
In contrast to the results obtained in this study, Key et al. (15) reported a signiﬁcant positive correlation (r 5 0.37) between PUFA and T in male vegetarians and omnivores. Our results showed a nonsigniﬁcant correlation between PUFA and T and a signiﬁcant negative correlation between the PUFA/SFA ratio and T.