Endurance athletes perform better if they ban cookies and other starch and sugar-loaded foods from their diet, and replace them with almonds. A human study, involving eight cyclists and two triathletes, that Chinese researchers published in the Journal of the International Society of Sports Nutrition suggests this.
Almonds contain mono-unsaturated fat and – compared with other nuts – lots of protein. And the protein contains relatively large amounts of the amino acid L-arginine. In addition, almonds contain phenols such as isorhamnetin-3-O-rutinoside. Isorhamnetin resembles quercetin and is synthesised in the body from quercetin.
The 3-O-rutinoside group is also found in the quercetin-based rutin molecule. As quercetin in the body is converted into isorhamnetin, rutin is probably converted into isorhmnetin-3-O-rutinoside. But this substance is also contained, readymade, in almonds.
Nutrition for athletes
So what effect do almonds have on athletes? This is the question that researchers at the National Institute of Sports Medicine in Beijing wanted to answer. They conducted an experiment in which they gave athletes 75 g almonds [3 handfuls] every day for four weeks [ALM]. On another occasion the researchers gave the same subjects cookies containing the same amount of kilocalories [COK].
After the subjects had eaten almonds or cookies for four weeks, the researchers got them to first cycle for just under two hours at 50-60 percent of their VO2 max. After a short rest the athletes then had to cycle as far as they could in a timed ride of 20 minutes [TT]. When the subjects had eaten almonds they could cycle a significantly greater distance than when they had eaten cookies.
BL = performance before the experiment started.
During the timed ride the subjects used less oxygen and burned more carbohydrates when they had eaten almonds, as the figure below shows.
The researchers suspect that the combination of L-arginine [the athletes consumed 2 g a day more L-arginine than normal when they ate almonds] and phenols in almonds contributed to the improvement in performance that was measured. This combination boosts the concentration of nitrogen monoxide in the muscle tissue of the athletes, the Chinese think. As a result the athletes were able to perform intensive exercise, during which they burned carbohydrates, for longer.
The effect of almond consumption on elements of endurance exercise performance in trained athletes.
Almonds are a healthy tree nut food with high nutrient density. Their consumption has been shown to ameliorate oxidative stress, inflammation, etc. The objective of the study was to examine the effect of almonds on elements of endurance exercise performance in trained athletes.
A 10-week crossover, placebo controlled study was conducted. Eight trained male cyclists and two triathletes were randomly assigned to consume 75 g/d whole almonds (ALM) or isocaloric cookies (COK) with equal subject number. They consumed the assigned food for 4 wks and then the alternate food for another 4 wks. They underwent 3 performance tests including 125-min steady status exercise (SS) and 20-min time trial (TT) on an indoor stationary trainer at the start of the study (BL) and at the end of each intervention phase. Venous blood was collected in the morning prior to the performance test for biochemical measurements and finger blood during the test for glucose determination. Carbohydrate and fat oxidation, energy expenditure, and oxygen use were calculated using respiratory gas analysis.
ALM increased cycling distance during TT by 1.7 km as compared BL (21.9 vs. 20.2 km, P?=?0.053) and COK increased 0.6 km (20.8 vs. 20.2 km, P?>?0.05). ALM, but not COK, led to higher CHO and lower fat oxidation and less oxygen consumption during TT than BL (P?< ?0.05), whereas there was no significant difference in heart rate among BL, ALM and COK. ALM maintained higher blood glucose level after TT than COK (P?0.05). ALM had higher vitamin E and haemoglobin and lower serum free fatty acid (P?0.05), slightly elevated serum arginine and nitric oxide and plasma insulin (P?>?0.05) than BL, and a higher total antioxidant capacity than COK (P?< ?0.05). CONCLUSIONS: Whole almonds improved cycling distance and the elements related to endurance performance more than isocaloric cookies in trained athletes as some nutrients in almonds may contribute to CHO reservation and utilization and effective oxygen utilization. The results suggest that almonds can be incorporated into diets of those who undertake exercise training for performance improvement. PMID: 24860277 [PubMed] PMCID: PMC4031978 Source: http://www.ncbi.nlm.nih.gov/pubmed/24860277