The Latest from the Sports Foods Front
By Nancy Clarke, MS, RD
Are there special nutrients or components of food that can really help runners go faster and stronger? Can they be consumed in the form of whole foods or do we need special commercial supplements? At a 2014 meeting of Professionals in Nutrition for Exercise and Sport (PINESNutrition.org), exercise researchers from around the globe discussed that topic and provided answers to these and other thought-provoking questions.
Is there any difference between consuming pre-exercise caffeine in the form of pills, gels or coffee?
Regardless of the source, caffeine is a popular way to enhance athletic performance. Take note: High doses of caffeine (2.5 to 4 mg/lb body weight; 6 to 9 mg/kg) are no better than the amount runners typically consume (1.5 mg/lb; 3 mg/kg). Hence, drinking an extra cup of coffee is unlikely to be advantageous, particularly when consumed later in the day before an afternoon workout when it could end up interfering with sleep.
Do Montmorency cherries offer any benefits to sports performance? If so, what's the best way to consume them?
Tart cherries (and many other deeply colored fruits and veggies) are rich in health-protective antioxidants and polyphenols. Tart cherries can reduce inflammation, enhance post-exercise recovery, repair muscles, reduce muscle soreness and improve sleep. Runners who are training hard, doing double workouts or traveling through time zones would be wise to enjoy generous portions. Yet, to get the recommended dose of cherries that researchers use to elicit benefits, you would need to eat 90 to 110 cherries twice a day for seven days pre-event. Most runners prefer to swig a shot of cherry juice concentrate instead!
What about food polyphenols such as quercetin and resveratrol?
Polyphenols are colorful plant compounds that are linked with good health when they are consumed in whole foods. Yet, polyphenol supplements, such as quercetin or resveratrol, do not offer the same positive anti-oxidant or anti-inflammatory benefits. An explanation might be that once in the colon, where most polyphenols go, parts leak into the bloodstream during heavy exercise. These smaller compounds create the anti-inflammatory effect. Athletes who routinely eat colorful fruits during endurance training offer their gut the opportunity to distribute good health!
Does curcumin reduce chronic inflammation?
Curcumin (an active constituent of tumeric, the spice that gives the yellow color to curry and mustard) has beneficial properties that have been shown to help prevent cancer, enhance eye health and reduce inflammation. Subjects with osteoarthritis who took curcumin supplements for eight months reported less pain (due to less inflammation) and better quality of life. Unfortunately, curcumin is rapidly metabolized and therefore has low bioavailability when consumed in the diet. To increase absorption, supplements often contain curcumin combined with piperine (black pepper extract).
Does green tea help improve body composition in athletes? What is the best way to take it?
Green tea reportedly enhances fat oxidation and helps with weight loss, particularly when combined with caffeine. But the amount of additional fat burned is minimal, and the 10 to 12 cups of green tea needed to create any effect is a bit overwhelming. Hence, most studies use a green tea extract. Because green tea has not been studied in lean runners, we can only guess that it is unlikely to offer a significant improvement in body composition.
Is watermelon juice a powerful stimulant for sports performance?
Watermelon juice is a source of L-citrulline, an amino acid that contributes to production of nitric oxide. Nitric oxide helps relax the blood vessels and thus enhances blood flow so more oxygen can get transported to the working muscles. One study with athletes who consumed L-citrulline supplements reports they attained a 7% higher peak power output as compared to when they exercised without L-citrulline.
Yet, when athletes were given watermelon juice (contains L-citrulline) or apple juice (that has no L-citrulline), the peak power was only slightly higher and the L-citrulline gave no significant benefits. Watermelon is a nourishing fruit and a welcome refreshment for thirsty athletes. You would need to eat a lot of watermelon to get the equivalent of L-citrulline found in (expensive) supplements. Your best bet is to enjoy watermelon in standard portions as a tasty addition to your sports diet.
What can be done with pea, hemp or other plant protein to make them as effective as whey for building muscle?
In general, plants (such as peas, hemp) contain less leucine than found in animal proteins. Leucine helps drive the muscle’s ability to make new protein. To increase the muscle-building properties of plant proteins, you need to either eat large portions of hemp or pea protein to get a bigger dose of leucine, or you can combine those plant foods with leucine-rich proteins, such as soy, egg or whey.
Your best bet to optimize performance is to optimize your total sports diet. No amount of any supplement will compensate for lousy eating.