Sports Nutrition Update

Sports Nutrition Update

—News You Can Use—

Goals: 1) To share recent sports nutrition information and dispel old myths. 2) Offer counseling tips that are effective for both casual exercisers and competitive athletes

Nancy Clark MS RD CSSD Sports nutrition private practice in Newton, MA Nancy Clark’s Sports Nutrition Guidebook, 5th Edition www.nancyclarkrd.com

Nancy Clark, MS, RD

Sports Nutrition Update

3) Validate that REAL food (as opposed to commercial sports foods) can effectively enhance performance. Nancy Clark, MS, RD

NEW: Engineered sports foods galore (Although sugar is deemed evil, sports drinks, gels and candies are OK?)

Topics include: • Engineered sports foods vs Supermarket foods (beets, tart cherry juice) • Concerns about “carbs” (wheat, sugar, processed grains) • Protein requirements and protein supplements • Recovery options (commercial foods vs chocolate milk) • Fluids (sports drinks, energy drinks, coffee) • Amenorrhea and the Female Athlete Triad

Nancy Clark, MS, RD

Nancy Clark, MS, RD

For trained people, sugar is unlikely “evil” Benefits of a 12-wk exercise intervention in obese people Pre- post study plasma insulin levels after breakfast

Pre-exercise sugar enhances performance STUDY:

Athletes with low glycogen stores biked hard for 45 minutes, then sprinted for 15 minutes

Trial

Improvements during final sprint

#1. Baseline: No fuel, only water

---

---Snack five minutes pre-exercise---

#2. Sugar (180 calories glucose) + Water

+10 %

#3. Candy Bar (270 calories) + Water

+10 %

#4. Breakfast 4 hrs before + Candy bar + Water

+20 %

(800 calories) Nancy Clark, MS, RD

Martins C et al. J Clin Endocrin Metab 2010;95:1609-1616

Nancy Clark, MS, RD

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One problem with engineered foods: “Flavor fatigue” CASE STUDY:

Female runner doing first 100 km trail run

Initial plan:

Gatorade Endurance + PowerBar Gel Blasts

Actual intake:

By mid-race, wanted savory/salty foods:

“Real foods” preferred during simulated adventure race (3 days) • Engineered foods - 14% total intake (Sports Drink, gels, energy bars, protein bars) • Supermarket foods - 86% total intake (more palatable) Sugary candy, chocolate, honey, sweetened condensed milk

broth, pretzels, bread with vegemite, sesame crackers, ginger cookies, chocolate bar Finish time:

Water, soft drinks, energy drinks, coffee Dried and fresh fruit

12 hours 49 minutes

3rd woman overall

Calories consumed: 2,700 (~900 from Gatorade Endurance) Calories/hour:

Rice, pasta, pizza, meat, sandwiches (salami, cheese, ham, tuna)

190 (average)

Nancy Clark, MS, RD

• Calories burned Percent replaced

• Av. expenditure 365 cal/hr Av. intake 225 cal/hr

Nancy Clark, MS, RD

Zimberg. Int’l J Sp Nutr 18(2):152, 2008

Siobhan, Int’l J Sport Nutr & Exerc Metab 2011;21:347-351

Variety of carbs get absorbed better Different sugars get absorbed using different transporters Better absorption = more energy to perform • Trained male cyclists consumed ~430 kcal//hour of— --Glucose (G) --Glucose + Fructose (G+F) --Water • They biked 2 hours

(55% VO-2 max)

Do commercial sports foods enhance performance better than real food? Sun-dried raisins are a cost-effective alternative to Sports Jelly Beans in prolonged cycling. • Same performance benefits during 2 h cycling followed by time trial. • Sensory acceptance score: significantly higher for raisins vs sports beans CONCLUSION: “Sun dried raisins are a natural, pleasant, cost-effective carbohydrate alternative to commercial Sports Jelly Beans and can be used during moderate to high intensity exercise”

then sprinted in a Time Trial

G + F = 8% faster time trial compared to G G + F = 19% faster compared to plain water Nancy Clark, MS, RD

24,500 60%

Currell K, Jeukendrup A Med Sci Sports Exerc. 40:275-81, 2008

Nancy Clark, MS, RD

Beets… really?

NEW: Foods rich in nitrates—like beets and

beet root juice—enhance performance

J Strength Cond Research 2011, 25(11):3150-56

• Beets are natural sources of nitrates, which convert to nitric oxide • Nitric oxide has beneficial effects on blood vessels, lowers blood pressure, enhances blood flow • Athletes can work harder due to better oxygen availability • The pigments in both red and yellow beets are also potent anti-oxidants

Nancy Clark, MS, RD

Nancy Clark, MS, RD

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Beetroot Juice Improves Performance in Well-Trained Rowers Six days of beetroot juice

Beet products are on the shelves…

(500 mL in 2 doses)—

—Improved rowing in 6 repeats of a 500-meter erg test – Greatest benefit in bouts 4 through 6 (the end of the event) – Average improvement: 0.4% (enough to win!) Consuming 500 ml beetroot juice 2 hours pre-exercise increases plasma nitrite by 138% Nancy Clark, MS, RD

Bond, IJSN 2012, 22:251-256

Nancy Clark, MS, RD

Efficacy of tart cherry juice in reducing muscle pain during running: a randomized controlled trial

NEW: Tart Cherry Juice reduces muscle soreness Claims made about tart cherry juice— • Antioxidant-rich super fruit • The “healing fruit” • Fights inflammation • Reduces muscle pain • Relieves joint/arthritis pain Nancy Clark, MS, RD

Are beets and cherries “super sports foods”? —What about grape juice, broccoli, tomatoes, etc…. Are all anti-oxidant rich foods just as effective?

--54 healthy runners, average age 35 y.o --Ran 3 sections of the hilly Mt. Hood to Coast Relay Race (~28 hours) --Each day of the week prior, they drank 24 ounces (2 bottles) tart cherry juice or placebo cherry drink (~400 calories) --Tart cherry group reported less pain than the placebo group (“Pain score”: 12 vs 37) --The runners expressed interest in using the drink in the future

Nancy Clark, MS, RD

NEW:

Kuehl et al. J Int’l Society Sports Nutrition 2010; 7:17

“All natural” foods are superior

Do they contribute to lower iron intake?

Hopefully! This research was funded by the companies that make beet root juice and tart cherry juice. These companies now have data to make advertising claims.

Nancy Clark, MS, RD

IRON: 15% RDA

2% RDA

45% RDA

Nancy Clark, MS, RD

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Low iron intake contributes to anemia -Anemia

(hemoglobin