Swim Sci

Swim Sci

Friday

Friday Interview: Dr. Christine Rosenbloom

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
I am Christine Rosenbloom, PhD, RD, CSSD, and I am a registered dietitian and a board certified specialist in sports dietetics through the Academy of Nutrition and Dietetics. I taught nutrition at Georgia State University for 30 years before “retiring” from teaching in 2010. I’ve worked with athletes since 1989; first at Georgia Tech and currently with the 300+ athletes at Georgia State University. In 2010 I started a food and nutrition consulting business and you can see examples of my work at my website at www.chrisrosenbloom.com.


2. You recently wrote a brief article for USA Swimming regarding nutrition for vegetarian and vegan athletes; could you briefly discuss your recommendations?
The choice to be a vegetarian or a vegan can be a healthful choice for an athlete. Those who abstain from animal protein usually eat more fruit, vegetables and whole grains than meat eaters. Vegan diets can be more challenging for an athlete because choosing protein-rich plant foods requires more planning to make sure all of the essential amino acids are consumed and plant-based protein is slightly less digestible than animal protein. Good protein sources for vegan athletes include brown rice, protein-enriched pasta (like Barilla Plus protein and omega-3-enriched pasta), nuts, tofu, soy milk and soy cheese and soy yogurt, tempeh, peanut butter, and beans and peas (black beans, kidney beans, black-eyed peas and lentils).

Nutrients that could be in short supply for vegans include calcium, iron, zinc, iodine, magnesium, vitamin D, vitamin B-12, and riboflavin. Some vegan food choices to get these nutrients include:

Calcium; calcium-set tofu, calcium-fortified orange juice, soy, rice and almond milk, broccoli, kale, greens (collards, turnips), almonds, tahini, blackstrap molasses
Iron: dried beans and peas, nuts and seeds (sunflower seeds, etc.), whole grain breads and cereals, root vegetables and dried fruit (raisins, etc.)
Zinc: dried beans and peas, nuts and seeds, soy foods and soy "burgers"
Iodine: iodized salt and seaweed (kombu)
Magnesium: beans, nuts and seeds, whole grains, leafy green veggies
Vitamin D: fortified foods (check labels of soy products to see if vitamin D is added), sun-dried mushrooms
Vitamin B12: nutritional yeast; vitamin B12 is only found in animal foods so look for soy foods that have added vitamin B12
Riboflavin: whole grains, fortified breads and cereals, tofu, nuts, seeds, bananas, asparagus, figs, avocado
One other point I made to the young woman who asked me about vegan diets was on fiber intake. While most Americans don’t get enough fiber, vegans can get too much fiber and for athletes that can mean excess gas, bloating and stomach upset. I remember talking to a college soccer player who had a lot of GI upset…turns out she was a vegan who was eating 75 grams of fiber a day (recommended fiber intake is about 25 grams a day for women). A lot of the fiber she was eating came from high fiber energy bars and the type of fiber in most bars is inulin which can cause GI symptoms when over consumed.
 

3. For swimmers, what are the most common dietary recommendations you suggest?
I focus on eating regularly throughout the day and timing intake around practice. I think nutrition is most important to support training; nutrients can actually help the muscles adapt to the training stimulus. Too many athletes go for long periods of time without eating and then calorie load at night (not unlike a lot of non-athletes!). It takes thoughtful planning to make sure that food is available to support your workouts. That is where a registered dietitian with sports experience can be helpful; we can translate nutrition into food plans that work for an individual.

4. What supplements do you frequently suggest?

I take a “food first” approach with the athletes I work with. I always look for ways to add a serving of food that is nutrient-rich before I suggest a supplement. If a supplement is needed, look for a high quality supplement that lives up to its marketing hype. I suggest looking for the USP symbol…that indicates that the supplement contains what it says it contains and the ingredients are of high quality. I work with athletes who are drug tested so it is important to careful that a supplement doesn’t contain a banned substance.

5. What are your views on creatine?

I have suggested creatine to some strength and power athletes (football players, sprinters) because it can increase the training stimulus by increasing muscle creatine content by about 20%. Creatine is safe in moderate doses but the effects may fade after 2 months of use. I don’t recommend creatine for endurance athletes, for anyone with high risk of kidney disease (people with diabetes or high blood pressure), or for anyone under the age of 18 years.

6. For vegan/vegetarian athletes, do you suggest protein powders? If so, what kinds and why?
I don’t recommend protein powders, but if protein intake cannot be achieved through diet, a whey protein powder mixed with water can provide high quality protein and the amino acid leucine, which seems to be the trigger to muscle protein stimulus.
 

7. What food recommendations do you suggest for before, during, and after a workout?
I wrote an entire article on this so for more details see Nutrition Today, 2012; 47(2):63-69. Before a workout, I suggest a 25-30 gram carbohydrate-rich snack an hour diving into the pool. A mini-cinnamon raisin bagel has 25 grams of carbs, so that give you an idea that it doesn’t have to be a big meal. During a workout, a snack is a good idea for the workout is longer than an hour; for a recreational swim, a snack is not needed. After a workout, what you eat depends on when you plan to eat your next meal and if you plan a hard workout for the next day. If you are going to eat within an hour of a workout, concentrate on replacing fluid loss and then eat a meal with quality carbs, lean protein and healthy fats. If you have a hard workout planned for the next day, then start eating within the hour after a workout to replace lost glycogen.


8. Does do you suggest for swimmers at a competition?
Plan to pack familiar foods that you know you will tolerate. This is not the time to try a new carbohydrate gel or energy drink. Easy to pack foods that require no refrigeration include orange sections, peanut butter or almond butter on crackers, trail mix with dried fruit, string cheese, and sports drinks. I suggest freezing a bottle of your favorite sports drink and use that as a cold pack for cheese or yogurt…by the time you are ready for the drink it will be thawed.

9. Prior to a taper meet, do you recommend carbohydrate loading? If so, how should it be performed?

 I rarely recommend carb loading; if you are eating quality carbs in the days leading up to a competition you will have ample carbohydrate in your muscles for the event. Carb loading can lead to a feeling of “heavy” muscles due to the extra water that is stored along with the carbs.

10. What research or projects are you currently working on or should we look from you in the future?
I recently edited the 5th edition of Sports Nutrition: A Practice Manual for Professionals (2012, Chicago, IL: Academy of Nutrition and Dietetics) and I have an article of stress fractures in athletes coming out in the spring. I also just completed a chapter of nutrition for elite athletes for an IOC publication that is currently in press.


Thanks Dr. Rosenbloom

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Tuesday

Effects of Vitamin C and E on Training Adaptations

Background
Many swimmers consume supplements and nutritional drinks around workouts. These drinks range in their purpose, but many are designed to improve recovery. 

Physiologist have been debating the subject of inflammation and its role on recovery. In fact, Kelly Starrett, CrossFit advocate, recently started a large internet debate on the effectiveness of ice. A lot of his argument pertained to inflammation as it reiterates the point, do we want to resolve inflammation following exercise or does this use negate the beneficial effect of exercise?


Similarly, consumption of antioxidants following training is under scrutiny. 

After exercise plasma interleukin-6 (IL-6) (a cytokine which helps regulate inflammation) increases up to 100-fold, most predominantly in the skeletal muscle which secrete IL-6 into the circulation. However, this increase is likely less in more trained athletes (Gokhale 2007).

Antioxidants have been suggested to decrease IL-6 in the muscle following exercise (Fischer 2004). IL-6 is also suggested to increase when exposed to free radicals (Kosmidou 2002). This association may be the cause of IL-6.

“The present study was undertaken to investigate the role of supplementation with the antioxidant vitamins C and E on the training-induced regulation of the systemic and skeletal muscle IL-6 responses to exercise (Yfanti 2012)”.

What was done
Twenty-one physically active men participated in a double-blinded, placebo-controlled design. These participants were split into a placebo or vitamin group (VT). The VT group received oral supplementation with vitamin C (500 mg/daily) and vitamin E (400 IU/daily) for 16 weeks. The training was 5 times/week for 12 weeks on the exercise bike. 
Performance and blood samples were the variables assessed in this study.

Results
Vitamin concentrations significantly increased in the blood after the 12-weeks in the VT group.  Two groups significantly improved VO2max, but not different from each other. 
IL-6 and IL-6 mRNA was attenuated after 12 weeks of endurance training. No differences were noted between groups. 

Discussion
Vitamin C and E may attenuate acute exercise-induced increase in plasma IL-6, but it does not appear to further decrease IL-6 levels after 12 weeks.


Practical Implication
This study suggests antioxidant supplementation does not decrease IL-6 production. However, it is not sure if this reduction results in long term benefits, as inflammation likely causes increases in strength.

Related Reading

Reference
Yfanti CFischer CPNielsen SAkerström TNielsen ARVeskoukis ASKouretas DLykkesfeldt JPilegaard HPedersen BK. Role of vitamin C and E supplementation on IL-6 in response to training. Appl Physiol. 2012 Mar;112(6):990-1000. Epub 2011 Dec 29.

Swimming Science Research Review 


This is a piece of the Swimming Science Research Review. Read Swimming Science Research Review November 2012 for a complete list of the articles reviewed.

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This will help you apply knowledge in the review to the pool deck, separating yourself from your peers!

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Wednesday

Effects of isocaloric carbohydrate vs. carbohydrate-proteinsupplements on cycling time to exhaustion

Richardson KL, Coburn JW, Beam WC, Brown LE. Effects of isocaloric carbohydrate vs. carbohydrate-proteinsupplements on cycling time to exhaustion.J Strength Cond Res. 2012 May;26(5):1361-5.

Background

Carbohydrates are thought to supply energy for the conversion of adenosine diphosphate to adenosine triphosphate (ATP). Prolonged exercise decreases glycogen stores, which require replenishing. After exercise, glycogen sensitivity increases, converting more carbohydrates to replenish glycogen directly following exercise.

Protein and carbohydrate drinks are thought to increase glycogen stores after exercise more than carbohydrates alone. Unfortunately, few studies have used the same amount of calories in these comparisons. Moreover, exercise studies suggest protein and carbohydrate drinks increase time-to-exhaustion.

“[T]he present study was conducted to examine the effect of frequent postexercise consumption of commercially available isocaloric CHO and CHO-Pro supplements on time to exhaustion during a subsequent bout of exercise (Richardson 2012).”

What was done

Seven men and four women received isocaloric drinks of either carbohydrate or protein and carbohydrate drinks every 30 minutes to measure recovery as measured by repeated time-to-exhaustion. The participants performed a warm-up, then an incremental cycling test to exhaustion. After exhaustion, the participants performed a cool down, followed by 3 hours of recovery where carbohydrate or carbohydrate and protein drink was consumed at 0, 30, 60, 90, and 120 minutes. The carbohydrate drink was 1.5 g/kg of body weight and the carbohydrate and protein drink had 1.2 g/kg of body weight carbohydrate and 0.3 g/kg of body weight protein.

After three hours, the participants performed another time-to-exhaustion test.

Results

There was no statistically significant difference in time-to-exhaustion between groups.

Discussion

The findings of this study conflicts with the findings of other literature. However, it appears that frequent isocaloric drink consumption results in similar recovery patterns. Other studies have used less frequent drink consumption, unfasted athletes, and more conditioned athletes, which are potential reasons for the different results.

Practical Implication

In swimming workouts and meets, where frequent sprints are performed, it appears either drink composition provides similar recovery benefits. Future studies, should look at different glycemic index carbohydrates and protein (whey used in this study). Moreover, studies with more conditioned athletes are necessary.
Swimming Science Research Review


This is a piece of the Swimming Science Research Review. Read Swimming Science Research Review October 2012 for a complete list of the articles reviewed.

Sign-up here to receive this month's edition and all future publications for only $10/month. Each edition covers articles ranging from biomechaincs, physiology, rehabilitation, genetic, and much more! These reviews explain the latest sports science research in straightforward language.

This will help you apply knowledge in the review to the pool deck, separating yourself from your peers!

And don’t worry, there’s no fixed commitment period, so if you don’t want to continue receiving the monthly publication, you can just cancel your payment whenever you want.

$10/month

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