Vegan for Life (26 page)

Carbohydrates serve as a primary fuel source in distance events, and people who try to cut back on “carbs” often compromise their performance.
Vegans are in good standing in this regard, since plant-based diets are typically high in carbohydrates.

According to the ACSM and ADA, low-fat diets—less than 20 percent of calories—are not associated with improved performance. Both groups recommend that athletes consume between 20 and 35 percent of calories from fat. A slightly higher fat intake may be advantageous for trained athletes since they use a higher percentage of fat for energy than non-athletes.

Iron needs don’t increase for strength athletes, but the American College of Sports Medicine recommends that all endurance athletes, especially distance runners, aim for iron intakes that are about 70 percent higher than the RDA.

This raises some questions for vegan endurance athletes. As we talked about in Chapter 6, the RDA for iron is increased by a factor of 1.8 for vegetarians. Like many other nutrition professionals, we believe that this is more iron than most vegetarians and vegans actually need. While some vegan endurance athletes might choose to take a modest daily iron supplement, we hesitate to recommend this since most vegans probably won’t need it. However, if you are a menstruating woman involved in endurance sports, you should probably get your iron checked on a regular basis. In fact, the ACSM and ADA recommend that all women athletes be regularly screened to assess their iron status, and screening can be especially important for teen athletes and pregnant women.

A number of supplements, which include amino acids and other protein-type compounds, are marketed to athletes to enhance their performance.

Creatine is the only nutritional supplement that has been consistently shown to improve strength and muscle mass in strength athletes in a large number of clinical trials. It’s thought to reduce fatigue during repeated, short bursts of intense exercise—the type that occurs with weight lifting, sprinting, soccer, rugby, and hockey. Less fatigue during sprinting and weight lifting means increased training and greater results.

Humans synthesize creatine in their liver and kidneys, and meat-eaters consume around 1 to 2 grams of creatine per day (although about 30 percent of it is destroyed in cooking). There is no creatine in vegetarian diets, though, and not surprisingly, vegetarians have lower levels of creatine in their blood, urine, red blood cells, and muscle tissue. Some studies have shown that vegetarians benefit more from creatine supplementation than meat-eaters.
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Fortunately, creatine supplements are vegan.

Creatine supplements are usually taken in two phases for loading and maintenance.

Loading:
Take 20 to 30 grams of creatine per day, divided into small doses over the course of the day, for a total of six days.

Maintenance:
The usual dose of 2 grams per day is meant for meat-eaters, which means that the dose for vegans may be closer to 2.7 to 3.4 grams per day. Some researchers suggest taking creatine only every other month to maximize its effects. Taking it with a sugar solution, such as a sports drink or fruit juice, increases the rate at which muscles absorb creatine.

According to the ACSM, the most common adverse effects of creatine supplementation are fluid gain, cramping, nausea, and diarrhea. Although its use is widely debated, the ACSM says that it is generally considered safe for adults. That said, there have been anecdotal reports of dehydration, muscle strains or tears, and kidney damage, so it’s important to let your health-care professional know if you are taking creatine.

Carnitine (also known as L-carnitine and acetyl-L-carnitine) is an amino acid found in meat and dairy products. It’s needed for fat metabolism and is promoted for weight loss and improved performance. According to the ACSM, however, it hasn’t been shown to help with either.

While there is very little carnitine in plant foods, it can be synthesized by the liver and kidneys. Vegans, vegetarians, and people who consume lower-fat, high-carbohydrate diets have lower blood levels of carnitine. There is no indication that this is unhealthy, and we don’t know if it has any bearing on athletic performance. In one study, vegans who took supplements of 120 milligrams of carnitine per day for two months excreted more carnitine in their urine, but the levels in their plasma didn’t increase significantly. This suggests that most of the carnitine was being lost in the urine.
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There is no evidence that vegans need to take carnitine, but since non-vegetarians typically eat 100 to 300 milligrams of carnitine per day, it is probably safe for vegans to take supplements providing that amount. Solgar brand carnitine is made by yeast fermentation of beet sugar and is one option available to vegans. If you take carnitine, watch for side effects, including nausea and diarrhea.

Carnosine (also known as beta-alanyl-L-histidine) is a molecule made up of two amino acids, beta-alanine and histidine. Animals, including humans, produce it in various tissues, especially the muscles and the brain. Plant foods don’t contain any, and one study has shown that vegetarians have 50 percent less carnosine than meat-eaters in their muscle tissue.
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Although the amino acid beta-alanine isn’t required in the diet (the body makes its own), beta-alanine supplements have been shown
to increase muscle carnosine levels. In fact, only supplements of beta-alanine, not carnosine itself, have been tested on athletic performance in human subjects.

In the ACSM position paper, beta-alanine doesn’t appear on the list of performance enhancers “that perform as claimed.” But about half a dozen studies have shown that approximately 6 grams of beta-alanine in doses spread over a day, for a period of four or more weeks, results in improved ability to perform, particularly during bouts of cycling. Not all studies have shown a significant benefit, though.

The athletic performance of some individuals might benefit from beta-alanine supplementation, and vegetarians could possibly benefit more than non-vegetarians, although no studies have compared the two groups. Now Foods makes a vegan beta-alanine supplement.

Beta-alanine appears to be safe in amounts of 6 grams per day for up to ten weeks, although some people have reported mild numbness or tingling.

Amenorrhea, or a loss of menstruation, may affect as many as 65 percent of young women who are long-distance runners. Hormone changes, inadequate calorie intake, and low body weight are all thought to contribute to the problem. At one time, vegetarian women were believed to be at higher risk for developing amenorrhea, but that no longer seems to be the case.

Amenorrhea correlates strongly with poor bone health. Even though weight-bearing exercise protects bones, it doesn’t seem to compensate for the reduced bone formation that is seen in women who stop menstruating.

The best treatment for amenorrhea is to decrease exercise, increase calories, and, if necessary, increase body weight. Increasing calories by 200 to 300 per day and not exercising for one day per week is a reasonable approach to restoring a normal menstrual cycle. It is also crucial
for all female athletes to meet recommendations for calcium and vitamin D. Vegans may need to use calcium supplements to boost intake of this essential mineral.

Endurance athletes are likely to meet protein needs easily because of their higher calorie intake. Those engaged in weight training may need to put a greater emphasis on protein-rich foods. The following menu demonstrates one way in which those needs can be met.

T
ofu, soymilk, miso, and tempeh have been staples of Asian cuisine for centuries. But soybeans have also given rise to a new generation of products that include substitutes for ground beef, chicken nuggets, luncheon slices, hotdogs, cheese, and sour cream.

There is no doubt about it: Both the traditional and the more modern soyfoods have made it easier than ever to be vegan. And aside from their practical benefits, soyfoods offer some unique health advantages—but there have also been questions about their safety.

It’s no small topic: Approximately 2,000 soy-related papers appear in medical and scientific journals every year. This chapter, which looks at both the potential benefits of soy as well as some of the more controversial issues, is meant to help clarify the findings so you can make an informed decision about how these foods fit into your diet.

Soybeans are unique among legumes. They’re higher in protein and fat and lower in carbohydrate than other beans. While much of the fat is the polyunsaturated omega-6 type, soybeans are one of the few good plant sources of omega-3 fatty acids. The carbohydrate in soybeans is composed largely of oligosaccharides, which are sugars that stimulate the growth of healthy bacteria.

The soybean’s claim to fame, though, is its protein content. Soy protein is highly digestible and its amino acid pattern closely matches
human requirements. It is considered comparable to proteins from animal foods and, according to the protein rating system that ranks proteins based on their amino acid pattern and digestibility, is the most highly rated of all plant proteins.
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Soybeans are also good sources of iron, potassium, folate, and sometimes calcium. Although they contain absorption inhibitors like phytate and oxalate, iron
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and calcium
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are both easily absorbed from soyfoods. In fact, the iron in soy is present in a form called ferritin, which makes these foods somewhat unique.
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Preliminary research suggests that ferritin iron may be very well absorbed. The calcium in fortified soymilk is absorbed as easily as calcium from cow’s milk.
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Soybeans are the only commonly consumed food that contains nutritionally relevant amounts of isoflavones. These are members of a larger group of compounds called phytoestrogens, or plant estrogens.

Isoflavones bind to the same receptors in the body—a necessary step for biological action—that bind the hormone estrogen. This has led to one of the biggest misconceptions about isoflavones—namely, that they are the same as estrogen. They’re not. Instead isoflavones are among a group of complex compounds called SERMS, or selective estrogen receptor modulators.
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It’s the word “selective” that describes how different isoflavones are from estrogen. There are two types of estrogen receptors in cells, and estrogen binds equally to both of them. But isoflavones preferentially bind to one type of estrogen receptor and, as a result, they can act very differently from estrogen in some parts of the body. Depending upon which type of receptor dominates in a given tissue, SERMs can have estrogen-like effects—or anti-estrogenic effects or no effects at all.

Isoflavones are natural SERMS, but some drugs used to treat cancer and osteoporosis are also SERMS. For example, the osteoporosis drug raloxifene has estrogen-like effects on bone and possibly on LDL-cholesterol,
two areas in which estrogen is protective and beneficial. But raloxifene may have anti-estrogenic effects in the breast, thereby reducing breast cancer risk.
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