Key Points
- Eating a variety of foods is one key to healthy living and lifelong performance.
- Promote lifelong health by eating many different colorful foods, which contain important protective compounds such as antioxidants and phytonutrients.
- Omega-3 fatty acids reduce the risk of several diseases. However, try to get your omega-3s from food instead of supplements.
- Plants are rich sources of fiber, which contributes to a healthy gut and reduces the risk of certain chronic diseases.
- Products containing probiotics (yogurt, kefir, sauerkraut) might help you maintain a healthy digestive tract.
- Foods rich in vitamin C and omega-3s can help with joint health. But talk to a healthcare provider before you start using a joint supplement.
Years of heavy physical activity can take a toll on Warfighters. However, it is possible to be a long-term Warfighter if you build good habits early and sustain them throughout life. These good habits include a well-balanced eating plan, structured exercise program, and healthy body weight. A health-promoting lifestyle can minimize your risks of many of the chronic diseases or conditions associated with aging, such as arthritis, musculoskeletal injuries, weight gain, hypertension, heart disease, Type II diabetes, metabolic syndrome, and cancer. This chapter discusses some nutrients that might help you maintain a healthy life for the long run.
Principles of high-performance eating
The 3 principles of high-performance eating are variety, moderation, and quality. These principles are especially important for the long-term Warfighter to optimize health and performance. Consuming a variety of foods will help you obtain all the essential nutrients for a strong, healthy body. Eating the same foods is not only boring but decreases the opportunity to obtain all the essential nutrients from your diet. However, eating in moderation also promotes good health. Eating too much of anything can lead to overconsumption of calories, resulting in unhealthy weight. Finally, eat a variety of foods that are of high quality. Fruits, vegetables, whole grains, nuts, seeds, eggs, dairy products, lean meat, poultry, and fish are all high-quality nutrition. They provide a ready supply of energy, vitamins, minerals, and other nutrients to keep your body healthy.
Antioxidants and phytonutrients
Antioxidants and phytonutrients in foods offer potential health benefits beyond basic nutritional needs. Possible benefits of antioxidants and phytonutrients include:
- Optimizing muscle strength and endurance
- Preventing muscle and joint injuries or fatigue
- Enhancing immune function
- Preventing heart disease and diabetes
- Preventing high blood pressure
- Reducing pain and inflammation
It’s better to get antioxidants and phytonutrients from whole foods rather than supplements. Research suggests eating more of foods rich in antioxidants might protect against disease, but the same result has not been found for antioxidant supplements.1
Antioxidants
Oxidation, or the production of free radicals, is a normal consequence of metabolism, strenuous exercise, and exposure to sunlight, pollutants, chemicals, and extreme environments. Accumulation of free radicals in your body can result in structural and functional damage such as inflammation, infection, and muscle injury from exercise. It also contributes to aging and a host of illnesses, including cancer and heart disease. Antioxidants are molecules that can neutralize free radicals and render them harmless.
A well-balanced eating plan that consists of fruits, vegetables, whole grains, nuts, and seeds will provide antioxidants and other nutrients to support the body’s natural defense against free-radical threats and protect against tissue damage. The most well-known antioxidants are vitamins A, C, and E, beta-carotene, and the mineral selenium. However, those are only a few of the many substances. For a list of major antioxidants and food sources, see Table 4–2, Chapter 4.
Phytonutrients
Phytonutrients are chemical compounds found in plants that have numerous desirable effects on the human body. They can act as antioxidants, anti-inflammatory agents, or other protective agents. Eating a variety of colorful foods that contain phytochemicals (Table 16–1) might decrease the risk of developing certain cancers, diabetes, hypertension, and heart disease. At present, a recommended daily allowance for phytonutrients does not exist, but eating a variety of foods—including plenty of fruits and vegetables—will ensure adequate intake.
For more information on phytonutrients, visit the Produce for Better Health Foundation.
Table 16–1. Common Types and Food Sources of Phytonutrients2
| Type | Food Sources |
|---|
| Anthocyanins | Red and blue fruits such as acai, blueberries, blackberries, raspberries, cherries, plums; and vegetables such as eggplant, red onions, red potatoes, and radishes |
| Beta-carotene | Leafy green, orange, and yellow vegetables such as broccoli, spinach, collard greens, kale, sweet potatoes, carrots, and cantaloupe |
| Flavanones | Citrus fruits |
| Flavonols | Apples, apricots, beans, broccoli, cherry tomatoes, kale, pear, onions, cherries, tea, and dark chocolate |
| Flavones | Celery, parsley, thyme, and oregano |
| Isoflavones | Soybeans and soybean products such as tofu and soy milk, and edamame |
| Lutein | Leafy green vegetables such as kale, spinach, turnip greens, and lettuces, as well as broccoli, Brussels sprouts, and artichokes |
| Lycopene | Tomatoes, watermelon, pink grapefruit, and red peppers |
| Zeaxanthin | Green vegetables, citrus fruits, and eggs |
Omega-3 fatty acids
Omega-3 fatty acids are polyunsaturated fatty acids (PUFA) that are important for cell and tissue development and, particularly, heart and brain health. The important omega-3 fatty acids are alpha linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).
Fish (particularly oily fish such as sardines, salmon, trout, mackerel, herring, and anchovies) and seafood are excellent sources of EPA and DHA. The American Heart Association recommends eating two 3½-ounce servings of fatty fish per week.3 In general, the health benefits of eating fish outweigh any risks associated with heavy metal (mercury) toxicity.
Sources of ALA include tofu and other soybean products, canola and soybean oils, walnuts, Brazil nuts, and flaxseed. Flaxseed (linseed) oil is the most concentrated source of ALA.
HPRC's article on omega-3 fatty acids in food has more information, including a list of various foods high in omega-3s.
Fish-oil supplements
It’s best to get omega-3s from foods, but many people do not like or do not have access to foods high in omega-3s, so they commonly take fish-oil supplements. As with other dietary supplements, fish-oil supplements should be taken only under the supervision of a healthcare provider, especially if you have health conditions or take medications, because fish-oil supplements can prolong bleeding time and interact with some medications and health conditions.4 Fish-oil supplements are generally well tolerated, but possible unwanted effects include fishy aftertaste and gastrointestinal complaints.
Dietary fiber
Dietary fibers—non-starch forms of carbohydrate obtained from plants—are structural components that the human body cannot digest.5 Dietary fibers are classified as soluble or insoluble, and most fiber-rich foods contain some of both types (Table 16–2). These two types function differently in the body.
- Insoluble fiber adds bulk to stools and promotes regular bowel movements. A diet high in insoluble fiber commonly helps your body digest and eliminate meals faster and increases stool weight.
- Soluble fiber absorbs water and turns into gel in the intestines. This helps slow digestion and might have a positive effect on your cholesterol levels.
Table 16–2. Fiber-Rich Foods
| Type | Description |
|---|
| Insoluble Fiber | Wheat bran, whole grains, whole wheat, nuts, seeds, barley, brown rice, celery, broccoli, onions, tomatoes, grapes, dark leafy vegetables |
| Soluble Fiber | Oatmeal, barley, nuts, seeds, beans, lentils, peas, apples, oranges, pears, berries, cucumbers, carrots |
Because your body doesn’t digest or absorb dietary fiber, it isn’t considered a nutrient (unlike vitamins, minerals, protein, fats, and carbohydrates), but it is still an essential part of a healthy diet. Dietary fiber plays a role in reducing your risk for various chronic conditions such as gastrointestinal diseases, hypertension, diabetes, heart disease, and several types of cancer, including colon cancer. For these reasons, it’s important to get the daily recommendation for fiber (Table 16–3).
Table 16–3. Daily Fiber Recommendations6
| Age | Men | Women |
|---|
| 19–30 | 34 g | 28 g |
| 31–49 | 31 g | 25 g |
| over 50 | 24 g | 22 g |
It’s important to increase your intake of fiber gradually because eating too much fiber in a short period of time can cause bloating, cramping, and gas until your gut gets used to more fiber. Also remember to drink plenty of fluids throughout the day to help fiber pass through your gut. Fruits, vegetables, whole grains, and beans and legumes are great sources of fiber. Table 16–4 includes examples of foods and their fiber content. You also can find the grams of fiber in packaged foods by looking at the Nutrition Facts label. In general, Americans don’t consume enough fiber because their intake of fruits, vegetables, and whole grains is low.6
Table 16–4. Fiber Content of Various Foods7
| Food | Grams of Fiber | Food | Grams of Fiber |
|---|
| Apple with skin (3" diameter) | 4 | ½ cup black beans | 8 |
| Orange (3" diameter) | 3 | 1 cup cooked green beans | 4 |
| Banana (7–8 inches long) | 3 | 1 cup cooked asparagus | 4 |
| 1 cup whole strawberries | 3 | 1 cup cooked spinach | 4 |
Probiotics and prebiotics
Both probiotics and prebiotics can help you maintain a healthy gastrointestinal tract.8-9 Probiotics are “good” or “friendly” bacteria, while prebiotics are food compounds that promote the growth of “good” bacteria.10
Probiotics
Probiotics are live microorganisms (in most cases, bacteria) that help maintain the natural balance of bacteria in your intestines and promote a healthy digestive system. Food sources of probiotics include:
- Yogurt
- Fermented milk such as kefir or buttermilk
- Aged cheeses such as cheddar or Gouda
- Tempeh, a food made by controlled fermentation of cooked soybeans
- Soy beverages
- Sauerkraut, finely sliced cabbage fermented by various lactic acid bacteria
- Kimchi, a fermented dish made of seasoned vegetables, often cabbage
- Kombucha, a beverage produced by fermenting sweet tea with a culture of yeast and bacteria
- Miso, a Japanese food produced by fermenting rice, barley, and/or soybeans with salt and a mold
Daily consumption of probiotic-containing foods not only improves gut health but also might offer other health benefits such as reducing your risk of colon cancer, lowering blood pressure, improving immune function, preventing infections, and improving mineral absorption.
Consuming probiotics can be especially important during times of illness or injury when the “good bacteria” in your gut can be destroyed. This includes preventing the diarrhea caused by antibiotics. Antibiotics eliminate harmful bacteria that might cause illness, but they also destroy your “good bacteria.” A decrease in the number of beneficial bacteria can lead to other complications, such as intestinal illnesses and flare-ups of inflammatory bowel disease. Taking probiotics might help replace the “good bacteria” destroyed by antibiotics and restore the balance between “good” and “bad” bacteria in your intestines.
Prebiotics
Prebiotics are non-digestible carbohydrates that support the growth and activity of probiotics in your intestines.8 Prebiotics occur naturally in plants such as garlic, asparagus, and onion. Other foods containing prebiotics include oatmeal, barley, beans, whole grains, leafy green vegetables, berries, bananas, yogurt, and milk. Because prebiotics can boost the effects of probiotics, food manufacturers add synthetic prebiotics to many foods. Two prebiotics added to many foods are inulin and fructo-oligosaccharides (FOS).
It’s important to consume both probiotics and prebiotics for optimal gut health, ideally those that occur naturally in foods. For example, combining Greek yogurt with a banana offers both probiotics and prebiotics.
Joint health
Military training puts stress on your body. Over time, this can lead to damaged joints and other musculoskeletal injuries. A healthy weight and nutrient-rich foods, along with regular exercise (with rest days) and stretching, can help optimize the long-term health and performance of your joints. In particular, eat foods—such as oranges, Brussels sprouts, strawberries, red peppers, and kiwis—that are rich in vitamin C, an antioxidant that plays a role in the formation of collagen (the main component of connective tissue). Other foods such as salmon and other fish, English walnuts, flaxseeds and their oil, and canola oil provide omega-3 fatty acids, which help reduce your body's inflammation.
Many people with joint problems turn to dietary supplements to improve their joint health. Before taking dietary supplements for your joints, talk to your healthcare provider to determine the cause of your joint pain and appropriate treatment strategies. Much of the research looking at the effects of certain dietary supplements for joint pain have been conducted in patients with knee osteoarthritis. Although some people with osteoarthritis might experience small reductions in joint pain, the use of any dietary supplement should be discussed with a healthcare provider. In general, there isn't enough scientific evidence to recommend any particular dietary supplement or ingredient to improve joint health.11-20
Strategies for the long-term Warfighter
Good nutrition can keep you in top condition for a long and healthy career despite years of high stress, physically demanding trainings, and missions that take a toll on even the most agile Warfighter. As you think about your eating plan, focus on whole foods that are rich in vitamins, minerals, antioxidants, phytochemicals, omega-3s, and fiber.
Remember that good nutrition is a lifestyle. In other words, eating a recovery snack after a workout won’t optimize your performance if you don’t eat balanced meals throughout the day too. Once you have the basics down, special attention to nutrition and hydration before, during, and after exercise will help keep you mission-ready. Nutrition is an integral part of Warfighter health, performance, and readiness, but enough sleep and exercise, good mental health, and healthy relationships also are essential to achieve Total Force Fitness.
