In a recent study published in the European Journal of Clinical Nutrition, researchers investigated the relationship between dietary fatty acid consumption and serological steroid hormone-binding globulin (SHBG) and testosterone levels in middle-aged male residents of Eastern Finland.
Study: Dietary fat quality and serum androgen concentrations in middle-aged men. Image Credit: val lawless / Shutterstock
Background
Serum testosterone levels in males have been declining in recent decades, the causes of which are unclear. Low testosterone levels are linked to obesity, sexual dysfunction, metabolic syndrome, and diabetes mellitus type 2. Therefore, normal testosterone levels are crucial to male health. Age, body mass index (BMI), alcohol intake, physical activity, and smoking status impact testosterone levels.
Studies have indicated that changes in the quality of dietary fats may also affect serum testosterone levels. In particular, increased polyunsaturated fatty acids (PUFA) intake has been linked to lower serum testosterone. Although studies have investigated the link between the type of dietary fat consumption, namely PUFA, monounsaturated fatty acids (MUFA), saturated fatty acids (SFA) consumption, and androgen levels, the findings are contradictory. Further research could inform strategies and dietary interventions to improve male reproductive wellness.
About the study
In the present cross-sectional study, researchers explored the impact of individual dietary fatty acid consumption on androgen levels in middle-aged males.
The population-based study included 2,546 males (mean age, 53 years) who participated in the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD). Data were obtained at baseline KIHD examinations between 1984 and 1989 from 2,682 males aged 42 years, 48 years, 54 years, or 60 years at study initiation and resided in Kuopio city or neighboring communities.
The team excluded 59 individuals with missing data on serological androgen levels, 26 individuals with inadequate dietary intake data, 50 cancer patients, and one individual receiving hormonal therapy. Blood samples were obtained from all participants. Educational attainment and household income were assessed using self-administered questionnaires.
The KIHD annual Leisure-Time Physical Activity Questionnaire was used to determine physical activity levels. SHBG and testosterone concentrations were determined using time-resolved fluoro-immunoassays. Dietary intake was assessed at baseline using four-day food records, including one weekend and three weekdays.
Linear regression modeling was performed to determine the relationships between dietary MUFA, PUFA, SFA, and trans fatty acid (TFA) intake and serological SHBG and free and total testosterone levels. In addition, multivariable nutrient-density modeling was performed to determine the relationship between isocaloric nutrient replacements and androgen levels.
Results
After adjusting for age, calorie intake, and examination year, among 2,546 males, increased SFA consumption was related to elevated serological SHBG concentrations, free and total testosterone levels, and increased PUFA consumption with lower levels. However, the relationships were weakened and non-significant after adjusting for other potentially confounding factors. TFA and MUFA consumption was not related to androgen levels.
In isocaloric replacement models, dietary protein replacement with saturated fatty acids was related to elevated serological SHBG and total testosterone levels. In particular, replacing calories from protein with those from SFA was linked to 1.0 nmol/L higher SHBG levels and 0.3 nmol/L higher total testosterone in serum. Similar associations were obtained using energy-adjusted fatty acid consumption in grams per day. Excluding 1,021 males with a prior history of diabetes or cardiovascular disease yielded non-significant associations. The multivariate-adjusted isocaloric replacement analysis showed that replacing calories obtained from proteins with those obtained from saturated fatty acids increased SHBG levels by 0.7 nmol/L and testosterone concentrations by 0.1 nmol/L.
Individuals with increased SFA consumption had higher MUFA intake and a lower consumption of PUFA, vegetables, fruits, and berries. Higher SFA intake was also related to lower educational attainment and physical activity. Increased PUFA consumption was linked to lower SFA consumption, less cigarette smoking, higher MUFA, vegetable, berry, and fruit consumption, higher educational attainment, and more physical activity. Individuals with an increased MUFA intake had an increased consumption of PUFA and SFA, lower consumption of vegetables, fiber, fruits, and berries, and were less physically active.
Overall, the study findings showed no independent associations between dietary fats and serological androgen concentrations among middle-aged males. Nevertheless, substituting calorie intake from proteins with saturated fatty acids might elevate serological androgen levels. Further studies are required to determine causal associations between dietary fat intake and serological androgen concentrations. Future studies, such as randomized controlled trials, could include diverse populations to improve the generalizability of the study findings. Well-controlled studies with observational designs considering nutritional replacements could also yield valuable insights.
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