A well-known example is vitamin C, which can effectively fight viral infections, prevent or reverse disease caused by bacteria, and help the body detoxify organic and inorganic toxins.  Vitamin C also reduces the risk for cancer, strengthens connective tissues (collagen), and counteracts stress by increasing the adrenal´s production of cortisol. The dose required is set according to the body's need. Nobel Price Laureate Linus Pauling suggested that an optimal daily intake of vitamin C could vary from at least 250 mg up to 20 grams per day.  Because unabsorbed vitamin C attracts water into the gut, some people may experience loose stools, gas and/or diarrhea by ingesting only 1-2 grams at a time, while others with a higher level of stress may tolerate 5-6 grams or more. The dose that causes loose stools is called the "bowel tolerance" for vitamin C.  To avoid the laxative effect of high doses, it is best to take vitamin C throughout the day in smaller divided doses.
Meal supplements are used to replace or fortify meals. They may be designed for people with special needs, or for people with illnesses that may affect digestion capabilities and nutritional requirements. Meal supplements may contain specific blends of macronutrients, or proteins, carbohydrates, fats, and fiber. Some meal supplements consist of raw, unprocessed foods, or vegetarian or vegan options, or high protein and low fat composition. Meal supplements are available to support some popular diet programs. Meal supplements are often fortified with vitamins, minerals, herbs, and nutrient-dense foods.
In addition to diet, exercise and other lifestyle factors can also play an important role in bone health. Smoking and drinking too much alcohol can increase your chances of developing osteoporosis, while weight-bearing exercise (such as walking, dancing, yoga, or lifting weights) can lower your risk. Strength or resistance training—using machines, free weights, elastic bands, or your own body weight—can be especially effective in helping to prevent loss of bone mass as you age.
When it comes to carbs, the more natural and whole, the better. Go for complex carbs like 100% whole-grain breads and pasta, brown rice, starchy vegetables, legumes, nuts, seeds, low-fat dairy and plenty of fruits and vegetables. Limit simple sugars from refined grains, processed snack foods, sweets and sugar-sweetened beverages. Check out our Essential Guide to Carbs.
Your doctor may also be able to notify you of any other potential risks a supplement might pose to your health (especially if you're pregnant, have other medical conditions or are planning to have surgery), as well as offer guidance on the best dosage to take. If your doctor isn't comfortable with advising you on supplement use, ask if he or she can refer you to a qualified supplement-savvy health practitioner. But keep in mind that because of a lack of research on side effects, just how a supplement may interact with a medication isn't known.
Dairy. Women should get 3 cups of dairy each day, but most women get only half that amount.6 If you can’t drink milk, try to eat low-fat plain yogurt or low-fat cheese. Dairy products are among the best food sources of the mineral calcium, but some vegetables such as kale and broccoli also have calcium, as do some fortified foods such as fortified soymilk, fortified cereals, and many fruit juices. Most girls ages 9 to 18 and women older than 50 need more calcium for good bone health.
Junk foods, however, are designed to avoid this sensory specific response. They provide enough taste to be interesting (your brain doesn’t get tired of eating them), but it’s not so stimulating that your sensory response is dulled. This is why you can swallow an entire bag of potato chips and still be ready to eat another. To your brain, the crunch and sensation of eating Doritos is novel and interesting every time.
Nutritional supplements may be designed to provide specialized support for athletes. Some of these consist of high-protein products, such as amino acid supplements, while other products contain nutrients that support metabolism, energy, and athletic performance and recovery. People engaging in intense athletic activity may have increased needs for water-soluble vitamins, antioxidants, and certain minerals, including chromium. Sports drinks contain blends of electrolytes (salts) that the body loses during exertion and sweating, as well as vitamins, minerals, and performance-supporting herbs.