Investigation of niacin on parameters of metabolism in a physiologic dose: randomized, double-blind clinical trial with three different dosages.

The aim of this double-blind, placebo-controlled cross-over design trial was to assess the safety of a multi-vitamin preparation containing nicotinic acid in a physiological dose. Seventy-two healthy volunteers took part in this trial. At six consecutive time-points, we systematically documented blood pressure, pulse, skin temperature and flushing symptoms after an oral dose of up to 50.1 mg nicotinic acid. The results suggest that nicotinic acid in a dosage of 16.7 mg does not cause flushing symptoms. In higher doses up to 50.1 mg, flushing symptoms are sporadically possible. There was no physiologically relevant change regarding the central metabolic parameters blood pressure, pulse and skin temperature.

Regulatory effects of a fermented food concentrate on immune function parameters in healthy volunteers.

OBJECTIVE: Nutrition is known to influence the immune system and can thereby modulate resistance to infection. The objective of this clinical trial was to assess the influence of a cascade-fermented food consisting of fruits, nuts, and vegetables rich in polyphenols (Regulat) on the immune system in healthy volunteers. METHODS: The clinical trial was double-blinded and placebo-controlled. In total, 48 healthy men 20-48 y of age with a body mass index of 20-28 kg/m(2) were enrolled in the clinical trial. The group was characterized according to lifestyle parameters and only men with regular low to moderate intake of fruit and vegetables were enrolled. The intervention lasted for a period of 4 wk. Volunteers received Regulat twice daily or a placebo product (essence of vinegar). RESULTS: The intake of Regulat significantly enhanced intracellular glutathione content in lymphocytes (P < 0.05), monocytes (P < 0.05), and natural killer cells (P < 0.01). Furthermore, activation of natural killer cell cytotoxicity in response to interleukin-2 stimulation (P < 0.05), a reduction of total lipid peroxidation, and a reduction of soluble vascular cell adhesion molecule-1 (P < 0.01) and soluble intercellular adhesion molecule-1 (P < 0.05) as inflammatory blood markers were found in the Regulat but not in the placebo group. CONCLUSION: In summary, the results from this intervention study demonstrate promising physiologic effects of immune regulation on the innate immune system and antioxidative and anti-inflammatory parameters after Regulat supplementation. However, these promising results need to be confirmed in more volunteers with a more prolonged application to ensure significant beneficial effects of Regulat in the general population.