The Effect of Nutrient-Dense, Portion-Controlled Functional Foods in Overweight Men with Reduced Libidos: A Prospective, Pilot Study

Abstract

Background and Objectives: Aging and weight gain often lead to reduced male libido, testosterone levels, and reproductive health functions. Younger men, who have reduced libido due to no under-lying medical or environment cause, are often prescribed medications. Non-pharmacological treatment usually includes weight loss. Materials and Methods: The aim of this prospective, single-arm, four-month study was to evaluate the effect of a nutrient-dense dietary plan using portion-controlled, pre-packaged functional foods on body weight, sexual performance, free testosterone, semen volume, and sperm concentration in overweight men aged 20-50 years of age. Results: Eleven individuals began the study, and six completed it. Participants consumed either four or five nutrient-rich functional foods daily and ate mostly healthy foods otherwise. Baseline mean weight was 107±21 kg, decreasing to 97±24 by week 8, but was 104±19 at week 16. Mean waist circumference decreased at each measurement: 112±13 cm at baseline, 110±12 cm at week 8, and 108 ±11 cm at week 16. Everyone, except one subject who had no change, experienced a decrease in waist circumference of 2-8 cm. All participants for whom data were available experienced increases in salivary testosterone concentrations between 18 and 87 pg/mL; by week 4, all had normal readings. At baseline and throughout the study, all but one person had normal semen volumes (i.e., at least 1.5mL). Sperm concentrations were Optimal at baseline for three participants (i.e.,≥ 55 M/mL), and the remaining two had Moderate values (16-54 M/mL, inclusive). Sperm concentrations varied throughout the study with three men experiencing Moderate concentrations at week 4, and two had Low concentrations (i.e., 15 M/mL). At week 8, all five subjects had Moderate sperm concentrations. By week 12, four had Moderate readings and one had an Optimal sperm concentration; at week 16, this improved to three with Moderate readings and two had Optimal concentrations. Total sperm counts (semen volume x sperm concentration [in millions]) varied among the participants. Between baseline and week 16, two participants had a lower total sperm count (decrease of 12% and 50%), and three had increased counts (all had 40-45% increases). Sexual health was assessed via a questionnaire (Sexual Health Inventory for Men [SHIM]). Upon entry into the study, all participants had suboptimal SHIM scores (i.e.,  21); at the end, three of the six normalized. For the general quality of life questions, scores tended to be better for each quality of life indicator, except gastrointestinal issues (GI), which worsened over time. The greatest improvements were seen in energy level, diet quality, and passion. Conclusions: Overweight men with low libidos experienced benefits from consuming nutrient-dense functional foods for anthropometric measurements, quantitative measures of testosterone, semen volume, sperm concentration, and subjective measures of quality of life. These preliminary results are encouraging, and we are continuing to recruit more subjects to confirm these findings.