A healthy, balanced diet that includes whole grains, fruits, vegetables, lean meats, low-fat dairy and polyunsaturated oils should supply all your daily nutritional requirements. If you have medical conditions or take medications, you may require dietary recommendations to include supplements. Vitamin and mineral supplements may be advised for restricted diets when adequate nutrition cannot be consumed. Supplements may not benefit a nutritionally adequate diet and can cause toxicity by exceeding safe maximum intake levels. Maximum intake limits exist for many vitamins and minerals to prevent toxic effects such as cardiac problems, high blood pressure, hemorrhagic stroke and kidney or nerve damage. Please consult a doctor before taking supplements.
Calcium
Adults ages 19 to 50 years require 1,000 mg of daily dietary calcium for proper heart and nervous system function, blood clotting, and to maintain bones and teeth. A daily calcium intake of 2,500 mg exists as the maximum upper limit for adults. Many breakfast cereals contain calcium carbonate as an added calcium source and add significantly to percent daily value calcium intakes. Calcium carbonate is the active ingredient in some over-the-counter antacid tablets, and maximum safe intake limits are printed on the package label. One antacid tablet may contain 400 mg calcium. Recent research has linked calcium supplement use to as much as a 30 percent increased risk of heart attack. According to RxList, doses of calcium 500 mg or less are safer than large amounts as daily intakes greater than 1,200 mg are associated with increased risk of heart attack.
Vitamin D
The body needs vitamin D to absorb calcium for strong bones, to regulate calcium and phosphorus levels, and for immune system function. Recommended daily intake for adults is 600 IU, or 15 mcg. The body makes vitamin D from exposure of the skin to sunlight, and fortified foods such as milk and cereals also supply small quantities. Dosages in supplements vary greatly, and excess vitamin D may cause many toxic effects such as muscle weakness, vomiting, hyperlipidemia, hypercalcemia, tissue calcification, high blood pressure and cardiac arrhythmias. MedlinePlus warns against long-term use of more than the maximum intake limit of 50 mcg per day. Treatment for deficiency necessitates a doctor's supervision.
Vitamin B6
Vitamin B6, or pyridoxine, aids protein and amino acid metabolism, production of red blood cells and proper nerve function. The Institute of Medicine has set the recommended daily intake for vitamin B6 at 1.3 mg for adults ages 19 to 50 years and the maximum safe intake at 100 mg. A popular energy shot may contain 40 mg of vitamin B6 per 2 oz serving. As intake increases above 100 mg, adverse side effects increase, especially with long-term use. Side effects of vitamin B6 may include headache, tingling/numbness, lack of muscle control, paralysis and nerve damage.
Vitamin E
Vitamin E, or alpha tocopherol, retains antioxidant and anticoagulant properties. Excellent dietary sources include sunflower, vegetable oils and nuts. Daily adult recommended intake for vitamin E is 15 mg, or 22.5 IU for adults, with a maximum upper limit of 1,000 mg or 1,500 IU. Supplement dosages may vary from 100 to 1,000 IU per capsule. Toxic effects may include nausea, fatigue, double vision, increased bleeding, inhibition of platelet aggregation, muscle weakness and increased risk of hemorrhagic stroke.
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