by In a recent study published in the European Journal of Clinical Nutritionresearchers investigated the relationship between dietary fatty acid consumption and steroid hormone-binding globulin (SHBG) and testosterone levels in middle-aged male residents of Eastern Finland.
Study: Dietary fat quality and serum androgen concentration in middle-aged men. Image Credit: val Lawless / Shutterstock
Background
Serum testosterone levels in males have been declining in recent years, and the reasons for this are unclear. Low testosterone levels are linked to obesity, sexual dysfunction, metabolic syndrome, and diabetes mellitus type 2. Therefore, normal testosterone levels are critical to male health. Age, body mass index (BMI), alcohol intake, physical activity, and smoking status affect testosterone levels.
Studies have shown that changes in the quality of dietary fats may also affect serum testosterone levels. In particular, increased intake of polyunsaturated fatty acids (PUFA) is 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 acid (SFA) consumption, and androgen levels, the results are contradictory. Further research could inform dietary strategies and interventions to improve male reproductive fitness.
About the study
In the current cross-sectional study, the researchers explored the effect of individual dietary fatty acid consumption on androgen levels in middle-aged men.
The population-based study included 2,546 males (mean age, 53 years) who participated in the Kuopio Ischemic Heart Disease (KIHD) Risk Factor Study. Data were obtained at the KIHD baseline examinations between 1984 and 1989 from 2,682 men aged 42 years, 48 years, 54 years, or 60 years at study initiation and who lived in the city of Kuopio or neighboring communities.
The team excluded 59 individuals with missing data on serological androgen levels, 26 individuals with insufficient 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 resolved fluorescent immunoprecipitations. 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 intake of MUFA, PUFA, SFA, and trans fatty acid (TFA) and serological SHBG and free and total testosterone levels. In addition, multivariate modeling of nutrient density was performed to determine the relationship between isocaloric nutrient replacement and androgen levels.
Results
After adjustment for age, calorie intake, and year of examination, among 2,546 males, increased SFA consumption was associated with elevated serological SHBG concentrations, free and total testosterone levels, and increased PUFA consumption with lower levels. However, the relationships weakened and were not significant after adjusting for other potential confounding factors. TFA and MUFA consumption was not associated with androgen levels.
In isocaloric replacement models, replacing dietary protein with saturated fatty acids was associated with elevated serological SHBG and total testosterone levels. In particular, replacing calories from protein with those from SFA was associated with 1.0 nmol/L higher SHBG levels and 0.3 nmol/L higher serum total testosterone. Similar associations were found using energy-adjusted fatty acid consumption in grams per day. Excluding 1,021 men with a previous history of diabetes or cardiovascular disease the association was insignificant. The multi-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 consumption of SFA and lower consumption of PUFA, vegetables, fruits and berries had higher MUFA intake. Higher SFA intake was also associated with lower educational attainment and physical activity. Increased PUFA consumption was linked to lower SFA consumption, less cigarette smoking, higher MUFA, consumption of vegetables, berries and fruits, higher educational attainment, and greater physical activity. Individuals with increased MUFA intake had increased consumption of PUFA and SFA, less consumption of vegetables, fiber, fruit and berries, and were less physically active.
Overall, the study results showed no independent associations between dietary fats and serological androgen concentrations among middle-aged males. However, serological levels of androgens may be elevated if caloric intake from protein is replaced by saturated fatty acids. Further studies are needed to determine causal associations between dietary fat intake and serological androgen concentrations. Future studies could include different populations, such as randomized controlled trials, to improve the generalizability of study results. Well-controlled studies with observational designs considering nutrient replacement may yield valuable insights.
