If all you have time for is a quick snack from the gas station or drugstore, know that you do have options, and if you know what you're looking for, it will be easier to find. When we asked registered dietitians to recommend snacks to buy at the drugstore, they tended to go for things like nuts and seeds that pack plenty of flavor (hi, wasabi chickpeas), plenty of protein, and not a whole lot else.
Vitamins are micronutrients, or substances that the body uses in small amounts, as compared to macronutrients, which are the proteins, fats, and carbohydrates that make up all food. Vitamins are present in food, but adequate quantities of vitamins may be reduced when food is overcooked, processed, or improperly stored. For instance, processing whole wheat grain into white flour reduces the contents of vitamins B and E, fiber, and minerals, including zinc and iron. The body requires vitamins to support its basic biochemical functions, and deficiencies over time can lead to illness and disease.
Calcium: For adult women aged 19-50, the USDA recommended daily allowance is 1,000 mg/day. For women over 50, the recommended daily allowance is 1,200 mg/day. Good sources of calcium include dairy products, leafy green vegetables, certain fish, grains, tofu, cabbage, and summer squash. Your body cannot take in more than 500 mg at any one time and there’s no benefit to exceeding the recommended daily amount.
Thus, higher levels of vitamins and minerals may delay mitochondrial aging, speed up the repair of large molecules such as DNA and collagen, and generally improve other cellular functions. This is an important rationale for taking higher doses of vitamins and minerals than recommended reference intakes. Dietary supplements can slow the aging process, in part by reducing the harmful effects of free radicals, known to be involved in many diseases such as cardiovascular disease and cancer.  Naturally-occurring hormones and/or supplements of cofactors needed for optimal hormone production in the body can have a significant life-prolonging effect if the body produces less than optimal amounts.  This is especially relevant for those with a genetic predisposition for disease.
In addition, several independent organizations offer quality testing and allow products that pass these tests to display their seals of approval. These seals of approval provide assurance that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants. These seals of approval do not guarantee that a product is safe or effective. Organizations that offer this quality testing include:
Cholesterol. Cholesterol is found in foods made from animals, such as bacon, whole milk, cheese made from whole milk, ice cream, full-fat frozen yogurt, and eggs. Fruits and vegetables do not contain cholesterol. Eggs are a major source of dietary cholesterol for Americans, but studies show that eating one egg a day does not increase the risk for heart disease in healthy people.2 You should eat less than 300 milligrams of cholesterol per day. Check the Nutrition Facts label for cholesterol. Foods with 20% or more of the “Daily Value” of cholesterol are high in cholesterol.
A new twist on an old favorite ― if your favorite recipe calls for frying fish or breaded chicken, try healthier variations using baking or grilling. Maybe even try a recipe that uses dry beans in place of higher-fat meats. Ask around or search the internet and magazines for recipes with fewer calories ― you might be surprised to find you have a new favorite dish!
One exception, he says, is seniors, who may need additional B-12 because as we get older, we absorb less of it. Most of us should skip the supplements and get our Bs from grains, dark green vegetables, orange juice, and enriched foods. People with certain medical conditions or who take drugs that interfere with vitamin absorption may also require supplementation.
Dietary supplement labels may carry certain types of health-related claims. Manufacturers are permitted to say, for example, that a dietary supplement addresses a nutrient deficiency, supports health, or is linked to a particular body function (like immunity or heart health). Such a claim must be followed by the words, "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."
Iron is one of the keys to good health and energy levels in women prior to menopause. Foods that provide iron include red meat, chicken, turkey, pork, fish, kale, spinach, beans, lentils and some fortified ready-to-eat cereals. Plant-based sources of iron are more easily absorbed by your body when eaten with vitamin C-rich foods. So eat fortified cereal with strawberries on top, spinach salad with mandarin orange slices or add tomatoes to lentil soup.
It's still an open question, but there is no question that ALA represents a dietary difference between the sexes. For women, it's a healthful fat. For men with heart disease or major cardiac risk factors, it may also be a good choice — but men with more reason to worry about prostate cancer should probably get their omega-3s from fish and their vegetable fats largely from olive oil.
Sure, you don't know what you'll be in the mood for later, and will you even be hungry? Yes, probably. After all, increased snacking is one reason behind the rise in calorie intake over the past few decades, according to a 2011 study in PLOS ONE. "When you leave your office to go find something, that's when bad choices are made," says Schapiro. "That's when a hot pretzel, bag of candy, or donut can look very appealing." Make sure your desk (or fridge) is stocked with an emergency stash of snacks, like Greek yogurt, individual packs of nuts, dried fruit, and nitrate-free jerky.
A dietary supplement is a manufactured product intended to supplement the diet when taken by mouth as a pill, capsule, tablet, or liquid. A supplement can provide nutrients either extracted from food sources or synthetic, individually or in combination, in order to increase the quantity of their consumption. The class of nutrient compounds includes vitamins, minerals, fiber, fatty acids and amino acids. Dietary supplements can also contain substances that have not been confirmed as being essential to life, but are marketed as having a beneficial biological effect, such as plant pigments or polyphenols. Animals can also be a source of supplement ingredients, as for example collagen from chickens or fish. These are also sold individually and in combination, and may be combined with nutrient ingredients. In the United States and Canada, dietary supplements are considered a subset of foods, and are regulated accordingly. The European Commission has also established harmonized rules to help insure that food supplements are safe and properly labeled. Among other countries, the definition of dietary supplements may vary as drugs or other classes of ingredients used in supplement products.
Good sources of iron include liver, kidneys, red meat, poultry, eggs, peas, legumes, dried fruits and dark, green leafy vegetables. Three ounces of cooked chicken liver contains 7.2 mg of iron; a cup of cooked spinach contains 6.4 mg. Your health care professional will probably recommend iron supplements during pregnancy (probably starting at 30 mg per day).
Supplements are most likely to cause side effects or harm when people take them instead of prescribed medicines or when people take many supplements in combination. Some supplements can increase the risk of bleeding or, if a person takes them before or after surgery, they can affect the person's response to anesthesia. Dietary supplements can also interact with certain prescription drugs in ways that might cause problems. Here are just a few examples:
Dietary fiber is found in plant foods like whole-grain breads and cereals, beans and peas, and other vegetables and fruits. At least one study suggests that women who eat high amounts of fiber (especially in cereal) may have a lower risk for heart disease. High-fiber intake is also associated with lower cholesterol, reduced cancer risk and improved bowel function. And one long-term study found that middle-aged women with a high dietary fiber intake gained less weight over time than women who ate more refined carbohydrates, like white bread and pasta.
When it comes to omega-3 fatty acids (omega = ω) such as EPA and DHA, children may be given cod liver oil and served fish and/or other seafood 2-3 times a week. It is important to check the dose of vitamin A supplied, as it can be toxic in high doses, especially for children. One problem with cod liver oil today is that vitamin D has been removed during processing, thus changing the natural ratio of the two vitamins so that we ingest relatively too much of vitamin A. 
Keep healthy food readily available. When you get hungry, you’re more likely to eat the first thing you see on the counter or in the cupboard. Keep healthy food in easily accessible and visible places in your home and workplace. Put some fruits in a basket and place it on the kitchen counter, store healthy snacks at eye level in your pantry and stock up your fridge with small batches of cooked whole grains and fresh fruits and vegetables. At work, store quick bites like almonds, pistachios and dried berries in a jar and place it on your desk or in its top drawer.
Here, too, body size is the main difference between the needs of males and females. Despite all the hype about high-protein diets, our protein requirements are really quite modest — only about a third of a gram per pound of body weight. For a 125-pound woman, that amounts to about 42 grams, for a 175-pound man, 58 grams. That's a tiny difference, just about half an ounce a day.
For some simple suggestions about eating a healthy, balanced diet, check out the "New American Plate Concept" from the American Institute for Cancer Research. This concept suggests you fill your plate with two-thirds or more of vegetables, fruits, whole grains or beans and only one-third or less of animal protein. This simple principle can guide you toward healthier eating. For more details, visit http://www.aicr.org/site/PageServer?pagename=reduce_diet_new_american_plate.
It's easy to get sucked into the lure of the restaurant menu when you're hungry and everything looks good. You don't have to order the plain grilled chicken breast with steamed veggies—that would be boring. Order what you'd like, but balance the meal out with the rest of the day, says Zied. If you know you're going out for a steak and potatoes dinner, go easy on the meat and starch at lunch. Make sure you're also fitting in healthy fare like whole grains, fruit, veggies, and nuts and seeds in the other meals and snacks that day. That way a hunk of steak won't derail your diet and you'll leave happy.
Calories. Most times, women need fewer calories. That’s because women naturally have less muscle, more body fat, and are usually smaller. On average, adult women need between 1,600 and 2,400 calories a day. Women who are more physically active may need more calories. Find out how many calories you need each day, based on your age, height, weight, and activity level.
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.
It is possible to ingest too much of certain vitamins and minerals (vitamin A, calcium, iron, copper, selenium) which may exacerbate an existing imbalance or lack of another mineral (magnesium, zinc). It is also important to balance intake of fatty acids in the omega-6 and omega-3 series, as most people get too much omega-6 and not enough omega-3. Small children can be overdosed with adult doses of for example vitamin A or iron, and pills may be dangerous for babies or young children because they can get stuck in the throat. Therefore, I recommend consulting a doctor or nutritionist educated in orthomolecular medicine. Most people are likely to benefit from taking a broad-spectrum multivitamin/mineral supplement as a basic insurance against deficiencies.