However, the Norwegian authorities do admit that vitamin D supplements are needed during part of the year.  Only part of the year? One third of Norway is within the Arctic Circle. Norway has far too little sunshine (especially during winter months) to get adequate levels of vitamin D from UVB radiation on the skin. The authorities also recommend that pregnant women take folic acid to prevent birth defects, and omega-3-fatty acids may be advisable for those who do not eat fish regularly. Norwegians have a long tradition of giving children cod liver oil, which in a daily tablespoon provides enough vitamin A and D and essential fatty acids to cover basic needs.
A BMI of 25 to 29.9 is considered overweight and one 30 or above is considered obese. For an idea of what this means, a 5-foot 5-inch woman who weighs 150 pounds is overweight with a BMI of 25. At 180 pounds, she would be considered obese, with a BMI of 30. Keep in mind that the tables aren't always accurate, especially if you have a high muscle mass; are pregnant, nursing, frail or elderly; or if you are a teenager (i.e., still growing).
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.
An Anti-Inflammatory Diet PlanDiabetes Smart TipsLiving Well with Rheumatoid ArthritisLiving Well with Colitis or Crohn'sManage Your Child's ADHDMood, Stress and Mental HealthTalking to Your Doctor About Hepatitis CTalking to Your Doctor About PsoriasisTalking to Your Doctor About Rheumatoid ArthritisYour Guide to Diabetes ManagementYour Guide to Headache and Migraine PainYour Guide to Managing DepressionSee All
Consult your health care professional. Women of childbearing age may want to consider taking folic acid supplements to reduce the risk of having a pregnancy affected with neural tube defects. Many women and teenage girls don't get enough calcium or vitamin D, both of which are critical to healthy bones and avoiding osteoporosis. Some people with diabetes appear to benefit from chromium. Vegetarians, especially vegans, may want to consider supplements to obtain nutrients they aren't getting from animal products.
^ Martineau, A. R; Jolliffe, D. A; Hooper, R. L; Greenberg, L; Aloia, J. F; Bergman, P; Dubnov-Raz, G; Esposito, S; Ganmaa, D; Ginde, A. A; Goodall, E. C; Grant, C. C; Griffiths, C. J; Janssens, W; Laaksi, I; Manaseki-Holland, S; Mauger, D; Murdoch, D. R; Neale, R; Rees, J. R; Simpson Jr, S; Stelmach, I; Kumar, G. T; Urashima, M; Camargo Jr, C. A (2017). "Vitamin D supplementation to prevent acute respiratory tract infections: Systematic review and meta-analysis of individual participant data". BMJ. 356: i6583. doi:10.1136/bmj.i6583. PMC 5310969. PMID 28202713.
Vitamin A can become toxic when taken in large amounts (over 100,000 International Units) on a daily basis over time, as can vitamin D. Substituting beta-carotene for vitamin A can alleviate this risk. Very large doses of minerals taken over long periods may have toxic effects in the body. Dosages far exceeding RDA's of vitamins are not recommended, nor are large doses of other supplements.
Some supplements can have unwanted effects before, during, or after surgery. For example, bleeding is a potential side effect risk of garlic, ginkgo biloba, ginseng, and Vitamin E. In addition, kava and valerian act as sedatives and can increase the effects of anesthetics and other medications used during surgery. Before surgery, you should inform your health care professional about all the supplements you use.
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.
The majority of adults in the United States take one or more dietary supplements either every day or occasionally. Today's dietary supplements include vitamins, minerals, herbals and botanicals, amino acids, enzymes, and many other products. Dietary supplements come in a variety of forms: traditional tablets, capsules, and powders, as well as drinks and energy bars. Popular supplements include vitamins D and E; minerals like calcium and iron; herbs such as echinacea and garlic; and specialty products like glucosamine, probiotics, and fish oils.
The soil in areas with relatively low rainfall may in some cases contain an extremely high concentration of minerals, which is reflected in the plants growing there. This was well documented 70 years ago in the book Tomorrow's Food.  The Dentist George W. Heard found that the soil in Hereford, Texas, was exceptionally rich in minerals. Hereford became known as the "town without a toothache" after a newspaper article from January 29, 1942, reported that Hereford had the lowest incidence of tooth decay of any city in the United States.  Heard found that people in Hereford had exceptionally few dental cavities and also that the soil locally was especially rich in minerals. He emphasized that the population in the county ate unprocessed food and was drinking raw milk. 
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.
Dietary supplements are complex products. The FDA has established good manufacturing practices (GMPs) for dietary supplements to help ensure their identity, purity, strength, and composition. These GMPs are designed to prevent the inclusion of the wrong ingredient, the addition of too much or too little of an ingredient, the possibility of contamination, and the improper packaging and labeling of a product. The FDA periodically inspects facilities that manufacture dietary supplements.