Carbohydrate is the body’s primary fuel. It should therefore be little surprise when that low carb levels in muscles (muscle glycogen) frequently correlate with illness and injury – when the body is in a low energy state, many of its functions become compromised.

This study on twelve male runners assessed the effects of carbohydrate intake, with and without protein (PRO),on  the responsiveness of immune cells immediately after prolonged strenuous exercise. Each athlete undertook each of 3 feeding interventions, 1 week apart, in randomized order after 2 hr of running at 75% VO2max. The feeding interventions (acting as their own control), comprising a  placebo solution, a high-carb solution equal to 1.2 g CHO/ kg body mass (BM), and a carb + protein solution with an additional  0.4 g PRO/kg BM immediately post-exercise.

The number of circulating immune-cells, their responsiveness to stimulation, plasma insulin, and cortisol levels were all determined from blood samples collected pre-exercise, immediately and post-exercise.

The responsiveness of immune cells to bacteria declined in placebo, but was maintained in the trials with high carb, or high carnb + protein, for hours after exercise.

Adding protein yielded no extra benefit in this trial, but this was on top of a very aggressive carb intake. Many athletes would probably prefer to bear their body composition in mind and consume some protein calories in place of sugar. Either way – ensuring an adequate energy intake will improve performance, but also immune health. If you function – then you perform!.

Costa, R.J.S. 2011 Effects of Immediate Post-exercise Carbohydrate Ingestion With and Without Protein on Neutrophil Degranulation IJSNEM Volume 21, Issue 3, June Original Research205 – 213

B-vitamins are used throughout the body in almost every area of metabolism. They help reactions proceed in the body, impacting on releasing energy from food, turning genes on and off, and making new structures in the body. It has been suggested that athletes may have requirements due to their higher energy expenditure and greater demands for regenerating tissues.

This study examined the effect of high-intensity physical activity during training on the biochemical status of thiamine (B1) and riboflavin (B2) in athletes. Thiamin and riboflavin concentrations in whole blood of a group of 19 college-level swimmers (6 men and 13 women) were measured during a low-intensity and compared with measurements taken during a high-intensity training period. The researchers also kept tabs on body composition, energy expenditure during training, distance covered, resting metabolic rate, and dietary intake of calories and b-vits

Blood concentrations of B1 decreased significantly during the intensive-training period compared with the low intensity period; however, the concentration of B2 remained unchanged.

So, for both male and female athletes, B1 should B a priority if you increase training intensity! Look for whole grains like buck-wheat and unrefined wheat and jumbo-oats, as well as vegetables and even… marmite (you love it or you hate it)!

Sato, A, 2011 Dietary Thiamin and Riboflavin Intake and Blood Thiamin and Riboflavin Concentrations in College Swimmers Undergoing Intensive Training IJSNEM Volume 21, Issue 3, June 195 – 204