Know Your Vitamin And Mineral Dosage
Now that you know how to choose the right supplements, the question now is do you know how much vitamins or minerals you should take every day?
How would you know if your multivitamins are enough?
What is the threshold for vitamin deficiency and overdose?
Some people get lost in nutritional jargon. If you are just confused in computing the right amount of vitamin and mineral intake, you need to know the basic nutritional measurements set by the Institute of Medicine.
- The institute sets the RDA (Recommended Dietary Allowance) and the AI (Adequate Intake). These are the standards for setting the acceptable amount of vitamins and minerals to be consumed by an individual to remain healthy. RDA and AI are based on age and gender.
- The UL (Tolerable Upper Intake Level) is the maximum dose of vitamins and minerals that can be safely consumed by an individual. Vitamin overdose is computed based on this benchmark. Exceeding the UL will result to side effects and even more serious health problems.
The FDA also sets its own measurement of recommended nutritional intake, the Daily Value (DV). The DV is the sole nutritional measurement found on food packaging. Due to limited space, manufacturers can only include a single nutritional measurement: the amount of vitamins or nutrients needed to maintain an optimum health based on a 2000-calorie diet. Sometimes, the DV for a particular nutrient is the same as its RDA counterpart.
DV and RDA may yield to different measurements, but keep in mind that both are intended to guide us on knowing how much nutrients should we take to avoid diseases and malnutrition.
Some people tend to take too much supplements, hoping that high doses will mean more curative or preventive effects. Although exceeding the RDA and DV of vitamin and mineral could be harmful to health, this is not always the case. For instance, the RDA for vitamin D is 400 international units (IU) for people aged 60. However, the National Osteoporosis Foundation advises the elderly to take twice as much vitamin D (800-1,000 IU). This is the recommended range of vitamin D intake to keep their bones healthy.
How to Know the Maximum Dose
Since supplement overdose also increases health risks, it is important to know when it is unsafe to exceed RDA and DV limits.
The UL (Tolerable Upper Intake Level) is the most practical way to know how much is enough. If you are exceeding your RDA or DV, make sure that you are still below your UL. It is easy to exceed your RDA or DV if you are taking several multivitamins and supplements. Some multivitamins can increase your B6 intake 50 times as much as the RDA level. But beware that such dose can lead to neuropathic symptoms.
Remember these things to avoid vitamin overdose:
- Supplements are not intended to replace foods. Supplements should be taken sparingly. Getting a mouthful of supplements is not the answer to your nutritional problems. Eating a wholesome diet is still the best way to achieve optimum nutrition. Supplements should only be taken to fill small nutritional gaps. It should be as moderate as taking a multivitamin once a day.
- Each supplement has its own safety profile. That is why some supplements have higher UL relative to their RDA counterparts. Pay close attention to such supplements for they are likely to get you exceed your UL. Excess vitamin A, like other extra fat-soluble vitamins such as E and K, could accumulate in the body and become toxic. Selenium and iron are also toxic when taken in high doses.
- The UL sets the maximum limit for almost all sources of nutrients. The amount of nutrients obtained from both supplements and foods is often taken into UL measurement. So you have to examine your diet when you think you are nearing your UL.
- Many nutrients pose serious health risks when taken in high dosage. Always check the UL for certain nutrients if you feel you are using too much supplements. If you have a serious illness, ask for the advice of your doctor before taking food supplements. Supplements may have harmful reactions when taken with prescription drugs.
- The UL is not included on food labels. The public barely hears of UL. However, you can find the UL for each nutrient at government websites.
- Most supplements lack UL, even RDA or DV numbers. Only few vitamins and minerals have government-set limits. Nutritionists really do not know the ideal intake limit for most of the supplements in the market.
Although exceeding the safety threshold of nutrients seldom happens, it is worth seeking your doctor’s advice on the use of supplement, especially if you plan to take it in large doses.
RDA and UL Matrices for Vitamins and Minerals
The Institute of Medicine sets the RDA threshold for 24 nutrients. Also shown below are the corresponding UL number for each nutrient.
These figures apply to people aged 19 years and above. Pregnant and lactating women belong to a different nutritional group. Minors and pregnant or lactating women are advised to check with their doctors before taking supplements.
|Recommended Dietary Allowance (RDA) or Adequate Intake (AI)
Nutrients with AIs are marked with an (*)
|Upper Tolerable Limit (UL)
The highest amount you can take without risk
|Boron||Not determined.||20 mg/day|
(Vitamin B complex)
|Copper||900 micrograms/day||10,000 micrograms/day|
|Folic Acid (Folate)||400 micrograms/day||1,000 micrograms/day
This applies only to synthetic folic acid in supplements or fortified foods. There is no upper limit for folic acid from natural sources.
|Iodine||150 micrograms/day||1,100 micrograms/day|
This applies only to magnesium in supplements or fortified foods. There is no upper limit for magnesium in food and water.
|Molybdenum||45 micrograms/day||2,000 micrograms/day|
|Nickel||Not determined||1.0 mg/day|
|Phosphorus||700 mg/day||Up to age 70: 4,000 mg/day Over age 70: 3,000 mg/day|
|Selenium||55 micrograms/day||400 micrograms/day|
|Vanadium||Not determined||1.8 mg/day|
|Vitamin B3 (Niacin)||
This applies only to niacin in supplements or fortified foods. There is no upper limit for niacin in natural sources.
|Vitamin D (Calciferol)||
|22.4 IU/day||1,500 IU/day
This applies only to vitamin E in supplements or fortified foods. There is no upper limit for vitamin E from natural sources.