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:


The tiny gender differences in minerals other than calcium and iron depend on body size. But while the dietary requirements for selenium fit this rule, men may benefit from supplements of about 200 micrograms a day, a level about four times above the RDA. That's because both a clinical trial and an observational study suggest that selenium may reduce the risk of prostate cancer. It's far from proven, but it's something for men to consider.
While women tend to need fewer calories than men, our requirements for certain vitamins and minerals are much higher. Hormonal changes associated with menstruation, child-bearing, and menopause mean that women have a higher risk of anemia, weakened bones, and osteoporosis, requiring a higher intake of nutrients such as iron, calcium, magnesium, vitamin D, and vitamin B9 (folate).
If you lose weight suddenly or for unknown reasons, talk to your health care professional immediately. Unexplained weight loss may indicate a serious health condition. And even if it doesn't, simply being underweight is linked to menstrual irregularity, menstrual cessation (and sometimes, as a result, dental problems, such as erosion of the enamel and osteoporosis) and a higher risk of early death.
Compared to pharmaceutical drugs, supplements of most essential nutrients are quite harmless. However, some supplements may have poor quality, or contain toxic metals such as lead or cadmium. Therefore, it is the duty of our authorities to ensure that potentially hazardous products or supplements of poor quality are not sold, and that consumers are offered fair prices in a free market. An example where the Norwegian authorities do not follow up such basic duties is that pharmacies demand more than 1,600 Norwegian Kroner (about $190) per kg of vitamin C in powder form, which would cost less than $20 with free competition and no restrictions in permitted doses or outlets. 

Brigitte Zeitlin, M.P.H., R.D., C.D.N., founder of the New York-based BZ Nutrition, tells SELF, "Eating regularly throughout the day keeps your metabolism running at full speed, prevents dips in your energy, keeps you alert and focused, and [can help keep] your weight steady by preventing overeating at later meals." She and other experts recommend eating every three to four hours. If you don't, there are a number of unpleasant symptoms you may encounter.
Both your nutritional needs (the food and water) and your metabolism (how fast your body converts food to energy) change at this age. Your metabolism gets slower. Women lose about half a pound of muscle per year starting around the age of 40. That makes losing weight even more difficult. Some of the changes women experience are due to decreased hormones, reduced activity level, and medical conditions.

Proteins are chains of amino acids. Nine of these proteinogenic amino acids are considered essential for humans because they cannot be produced from other compounds by the human body and so must be taken in as food. Recommended intakes, expressed as milligrams per kilogram of body weight per day, have been established.[26] Other amino acids may be conditionally essential for certain ages or medical conditions. Amino acids, individually and in combinations, are sold as dietary supplements. The claim for supplementing with the branched chain amino acids leucine, valine and isoleucine is for stimulating muscle protein synthesis. A review of the literature concluded this claim was unwarranted.[36] In elderly people, supplementation with just leucine resulted in a modest (0.99 kg) increase in lean body mass.[37] The non-essential amino acid arginine, consumed in sufficient amounts, is thought to act as a donor for the synthesis of nitric oxide, a vasodilator. A review confirmed blood pressure lowering.[38] Taurine, a popular dietary supplement ingredient with claims made for sports performance, is technically not an amino acid. It is synthesized in the body from the amino acid cysteine.[39]
A person's caloric requirement depends on his body size and exercise level. Sedentary people of both genders will keep their weight stable by taking in about 13 calories per pound of body weight each day. Moderate physical activity boosts this requirement to 16 calories a pound, and vigorous exercise calls for about 18 calories a pound. On average, a moderately active 125-pound woman needs 2,000 calories a day; a 175-pound guy with a similar exercise pattern needs 2,800 calories. And like women, men will lose weight only if they burn more calories than they take in.
A similar problem with the level of minerals in the soil exists for the content of magnesium. Often when the soil gets depleted of magnesium from heavy use, this essential mineral is not included in soil amendment with fertilizers. Produce grown in soil with an adequate level of magnesium will contain more magnesium than produce grown in soil deficient in magnesium. Perhaps as many as 70-80% of the US population is magnesium-deficient, which causes many health problems. [24] Magnesium supplements (chloride, malate or citrate) can provide an adequate level when vegetables grown in soil with adequate magnesium are not available.
Eating a healthy diet doesn’t have to be overly complicated. While some specific foods or nutrients have been shown to have a beneficial effect on mood, it’s your overall dietary pattern that is most important. The cornerstone of a healthy diet pattern should be to replace processed food with real food whenever possible. Eating food that is as close as possible to the way nature made it can make a huge difference to the way you think, look, and feel.
Health care experts haven't reached a consensus on the issue of vitamin and mineral supplements. Many say that if you are healthy and eat a well-balanced diet, you don't need any. But not all of us eat a well-balanced diet. And sometimes, you may follow a nutritious diet and still be deficient. Many women fail to get the adequate amount of vitamins and minerals. Stress increases your need for vitamins and minerals, especially C, B-complex and zinc.
Fats contain both saturated and unsaturated (monounsaturated and polyunsaturated) fatty acids. Saturated fat raises blood cholesterol more than unsaturated fat, which may even help lower harmful cholesterol. Reducing saturated fat (most comes from meat, dairy and bakery products) to less than seven percent of total daily calories may help you reduce your cholesterol level. Whenever possible, replace saturated fat with monounsaturated and polyunsaturated fats.
An important take-home message is to focus on the types of foods you eat and your overall dietary pattern, instead of on individual nutrients such as fat, dietary cholesterol, or specific vitamins. There are no single nutrients or vitamins that can make you healthy. Instead, there is a short list of key food types that together can dramatically reduce your risk for heart disease.
In 1994, the United States Congress passed a law defining nutritional supplements, and requiring them to be labeled as dietary supplements and identified as not intended to be a substitute for certain foods. A nutritional supplement can be defined as a product intended for consumption in tablet, capsule, powder, soft gel, gel cap, or liquid form, and containing vitamin(s), mineral(s), herb(s), other botanicals, amino acids, or any combination thereof.
A study of dietary supplements sold between 2007 and 2016 identified 776 that contained unlisted pharmaceutical drugs, many of which could interact with other medications and lead to hospitalization.[79] 86% of the adulterated supplements were marketed for weight loss and sexual performance, with many containing prescription erectile dysfunction medication. Muscle building supplements were contaminated with anabolic steroids, and multiple products contained antidepressants and antihistamines. Despite these findings, fewer than half of the adulterated supplements were recalled.[79]
Fats contain both saturated and unsaturated (monounsaturated and polyunsaturated) fatty acids. Saturated fat raises blood cholesterol more than unsaturated fat, which may even help lower harmful cholesterol. Reducing saturated fat (most comes from meat, dairy and bakery products) to less than seven percent of total daily calories may help you reduce your cholesterol level. Whenever possible, replace saturated fat with monounsaturated and polyunsaturated fats.
^ Jump up to: a b Coghlan, M. L.; Haile, J; Houston, J; Murray, D. C.; White, N. E.; Moolhuijzen, P; Bellgard, M. I.; Bunce, M (2012). "Deep Sequencing of Plant and Animal DNA Contained within Traditional Chinese Medicines Reveals Legality Issues and Health Safety Concerns". PLoS Genetics. 8 (4): e1002657. doi:10.1371/journal.pgen.1002657. PMC 3325194. PMID 22511890.
In between meals, go ahead and have a snack. "When you go too long in between meals without eating, it is difficult to go into your next meal in control and avoid overeating,” Julia Levine Axelbaum, R.D., L.D., Bariatric Dietitian at NewStart Clinic, tells SELF. Of course, you'll want to be thoughtful about the kind of snacks you opt for. She explains that those that are high in protein, fiber, and complex carbohydrates will give you the energy you need to get through the day and keep you satiated from one meal to the next. On the other hand, those that are high in refined carbs and sugar will give you a sudden blood sugar spike that will eventually cause you to crash and feel even more tired.
Women need more of this mineral because they lose an average of 15 to 20 milligrams of iron each month during menstruation. Without enough iron, iron deficiency anemia can develop and cause symptoms that include fatigue and headaches. After menopause, body iron generally increases. Therefore, iron deficiency in women older than 50 years of age may indicate blood loss from another source and should be checked by a physician.
Before you take any supplements for disease prevention, it's important to know whether the potential benefits outweigh the risks. To make that conclusion, you need to look at the results of well-designed studies. A recent randomized trial in men suggested multivitamins have possible benefits for cancer prevention. For many of the other popular supplements, including vitamin D and omega-3 fatty acids, results from randomized controlled trials should be available within the next five years, according to Dr. Manson.

Plant oils, particularly seed and nut oils, contain ALA.[43] Food sources of EPA and DHA are oceanic fish, whereas dietary supplement sources include fish oil, krill oil and marine algae extracts. The European Food Safety Authority (EFSA) identifies 250 mg/day for a combined total of EPA and DHA as Adequate Intake, with a recommendation that women pregnant or lactating consume an additional 100 to 200 mg/day of DHA.[45] In the United States and Canada are Adequate Intakes for ALA and LA over various stages of life, but there are no intake levels specified for EPA and/or DHA.[46]


Vitamin B12.Vitamin B12 helps keep your red blood cells and nerves healthy. While older adults need just as much vitamin B12 as other adults, some have trouble absorbing the vitamin naturally found in food. If you have this problem, your doctor may recommend that you eat foods like fortified cereals that have this vitamin added, or use a B12 supplement.
Carbohydrates are one of your body’s main sources of energy. But most should come from complex, unrefined carbs (vegetables, whole grains, fruit) rather than sugars and refined carbs. Cutting back on white bread, pastries, starches, and sugar can prevent rapid spikes in blood sugar, fluctuations in mood and energy, and a build-up of fat, especially around your waistline. Learn more »
Nutrition is particularly important during pregnancy to ensure your health and the health of the baby. It's normal to gain weight during pregnancy—not just because of the growing fetus, but because you'll need stored fat for breast-feeding. The Institute of Medicine (IOM) recommends a gain of 25 to 35 pounds in women of normal weight when they get pregnant; 28 to 40 pounds in underweight women; and at least 15 pounds in women who are overweight when they get pregnant. The IOM has not given a recommendation for an upper limit for obese women, but some experts cap it as low as 13 pounds. If you fit into this category, discuss how much weight you should gain with your health care professional.
Young adults. Teen girls and young women usually need more calories than when they were younger, to support their growing and developing bodies. After about age 25, a woman’s resting metabolism (the number of calories her body needs to sustain itself at rest) goes down. To maintain a healthy weight after age 25, women need to gradually reduce their calories and increase their physical activity.
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. [36] 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. [37] This is especially relevant for those with a genetic predisposition for disease.
Calcium. As well as leading to osteoporosis, not getting enough calcium in your diet can also contribute to anxiety, depression, and sleep difficulties. Whatever your age or gender, it’s vital to include calcium-rich foods in your diet, limit those that deplete calcium, and get enough magnesium and vitamins D and K to help calcium do its job. Learn more »

Among other things, you need calcium to build healthy bones and teeth, keep them strong as you age, regulate the heart’s rhythm, and ensure your nervous system functions properly. Calcium deficiency can lead to, or exacerbate, mood problems such as irritability, anxiety, depression, and sleep difficulties. If you don’t get enough calcium in your diet, your body will take calcium from your bones to ensure normal cell function, which can lead to weakened bones or osteoporosis. Women are at a greater risk than men of developing osteoporosis, so it’s important to get plenty of calcium, in combination with magnesium and vitamin D, to support your bone health.


Always be sure you get regular servings of dairy products, calcium-rich tofu and greens, and calcium-fortified orange juice. Also, eat lean meat and/or high-quality protein combinations such as pinto beans and rice. Avoid fiber supplements as these bind calcium and other minerals in the intestinal tract. When this happens the absorption of essential nutrients decreases.


The new guidelines encourage eating more nutrient-dense food and beverages. Many of us consume too many calories from solid fats, added sugar and refined grains. The guidelines promote a diet that emphasizes vegetables, fruits, whole grains, fat-free or low-fat dairy products, seafood, lean meat and poultry, eggs, beans and peas, and nuts and seeds.
Another spin on the 80/20 rule, says Dr. Lipman: stopping eating when you're 80% full. That means slowing down and checking in periodically throughout the meal about what your body is saying. Does the food no longer taste great? Are you getting that "I don't really need any more feeling"? Thinking 80/20 as you eat can help slow you down and be more mindful. Being in tune with your body prevents overeating, he says.
As the science of nutrition continually evolves, researchers recognize that nutrients needed to maintain a healthy lifestyle must be tailored to the individual for maximum effectiveness. Recognizing that people are not all alike and that one size does not fit all when it comes to planning and achieving a healthful diet, the Institute of Medicine's dietary guidelines, titled "Dietary Reference Intakes for Macronutrients," stress the importance of balancing diet with exercise and recommends total calories based on an individual's height, weight and gender for each of four different levels of physical activity.
^ Fortmann, SP; Burda, BU; Senger, CA; Lin, JS; Whitlock, EP (Nov 12, 2013). "Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force". Annals of Internal Medicine. 159 (12): 824–834. doi:10.7326/0003-4819-159-12-201312170-00729. PMID 24217421.

Most Americans get far more protein than they really need. In theory, that may not be wise. Like carbohydrates, protein provides 4 calories per gram, and excess calories from any source will be stored as body fat. Excess dietary protein increases calcium loss in the urine, perhaps raising the risk for osteoporosis ("thin bones," more a worry for women) and kidney stones (a particular worry for men).


While what works best for one woman may not always be the best choice for another, the important thing is to build your dietary choices around your vital nutritional needs. Whether you’re looking to improve your energy and mood, combat stress or PMS, boost fertility, enjoy a healthy pregnancy, or ease the symptoms of menopause, these nutrition tips can help you to stay healthy and vibrant throughout your ever-changing life.
Say no to sugary drinks. The average American drinks around 45 gallons of soda each year, according to the Beverage Marketing Corporation. Other than the obvious risk of Type 2 diabetes and obesity, consuming sugary beverages can also cause liver damage, premature aging and anxiety. So, instead of sipping packaged juice or soda, go for unsweetened beverages or infused water.
The average woman should get 10 to 35 percent of her daily calories from protein. Protein helps prevent muscle tissue from breaking down and repairs body tissues. Sources of animal proteins include meat, fish, poultry, eggs, milk and cheese. Vegetable proteins include dried beans and peas, peanut butter, nuts, bread and cereal. (A three-ounce serving of cooked chicken contains about 21 grams of protein.)
Eat all the foods you enjoy—but the key is to do it in smaller quantities, says Elisa Zied, RDN, who has lost and kept off more than 30 pounds since her highest weight in high school. In fact, she says it's the number one change she made that's helped her maintain her smaller frame. "I didn't want to feel deprived as I had in previous attempts to lose weight," she says. The worst thing you can do is be too strict, then rebound by overeating because you're not satisfied.
5. Wrap unhealthy foods in tin foil. Wrap healthy foods in plastic wrap. The old saying, “out of sight, out of mind” turns out to have some truth to it. Eating isn’t just a physical event, but also an emotional one. Your mind often determines what it wants to eat based on what your eyes see. Thus, if you hide unhealthy foods by wrapping them up or tucking them away in less prominent places, then you are less likely to eat them.
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