Journal Title (Medline/Pubmed accepted abbreviation): Int. J. Sport Nutr. Exerc. Metab.
Page numbers: 381-392
doi (if applicable):
Summary of Background and Research Design
Background:Silica forms unique bonds with water molecules and is thought to enhance water retention during intense exercise. Its unique chemical structure might also help buffer lactate.
Hypothesis/Research Question:Does a silica-based mineral antioxidant supplement affect water retention and distribution, lactate build up, or aerobic performance?
Subjects:15 active men, age 23.6 ± 3.7 yrs
Experimental design:double-blind, randomized crossover
Treatments and protocol: Supplement: 2,400 mg mineral antioxidant supplement (MAC) per day for 7 days- 4 x 600 mg capsules spread out throughout the day. Each capsule contained 250 mg colloidal silicate mineral and 350 mg of rice bran flour. The silicate material was a proprietary combination of food grade silica, potassium carbonate, potassium citrate, and magnesium sulfate.
Placebo: An amount of rice flour equivalent to the dose of supplement.
Protocol: The participants went to the testing facility 5 times. The first session, they familiarized themselves with the protocol and VO2max measurements were acquired. 3 days later (Session 2), baseline measurements were acquired. Pre-exercise measurements were obtained and they drank 237 mL of water 30 min before exercise. For exercise, participants maintained 60-70 rpm on a stationary bike. Testing began with a 2 min warm-up at 20 W and then increased to 50 W. Every 3 sec the workload increased 1 W until the subjects could not maintain 50 rpm. Following this ride, they had a 10 min cool down of 50 rpm at 20 W. They drank 237 mL more water. post-exercise data were acquired 2 h later. The subjects then took either the MAC or a placebo (rice flour) for 7 days and then repeated the procedure (Session 3, Testing day 1). On testing day, they consumed 3 capsules of the appropriate supplement with the first 237 mL water and 1 capsule with the last 237 mL water. There was one week of washout. Session 4 involved no cycling, but an assessment of their body water. For the last 7 days, the other supplement (either MAC or the placebo) were taken and Session 5 involved the same cycling protocol as Session 2 (Testing day 2).
Body impedence was used to assess body water. Blood samples were collected for measurement of clinical safety variables.
Summary of research findings:
No significant differences between treatments were observed for: total body water, intracellular and extracellular water, serum lipid levels, whole-blood complete blood count markers (white blood cells, hematocrit, etc.), heart rate, blood pressure, rate of perceived exertion, blood lactate concentration, VO2max, time to exhaustion, or peak power. There were some within-group increases in total body and intracellular water, but these changes were of minimal physiological significance. Acute MAC supplementation appeared to be safe, causing no changes in any of the safety variables mentioned above.
Interpretation of findings/Key practice applications:
Previous studies have found that silica may reduce blood lactate in cycling time trials, so there may be some ergogenic effects of silica for some types of exercise (endurance vs. power, for example). However, these types of exercise still need to be determined as well as dosages (amount per serving and acute vs. chronic intake). Also, there may be certain types of athletes that respond better to silica dosing.