Can vitamin supplements really undo a poor diet? Many of us like to think so. Even the most intelligent, health conscious people believe that their one-a-day “miracle” vitamin will make up for a lack of fruits and vegetables. But, is it problematic to exceed the recommended upper intake level (UL) for any one nutrient?
In this fast paced lifestyle we lead, vitamin supplements seem like the obvious answer to ensure we meet our body’s vitamin and mineral needs. It is rare to exceed the UL for a nutrient from food sources but when taken in supplement form, especially when taking a variety of single nutrient vitamins, it’s easier to go over the UL.
If we look at calcium and vitamin D for example, we rarely hear anything about exceeding recommended intake. However, with so many new fortified foods, it’s far easier today to get more calcium and vitamin D than we need, than it was 20 years ago. “I do think calcium supplements and vitamin D are likely to be useful for women at risk for osteoporosis, especially if they don’t get enough from their diet. But overall, if people eat a healthy diet, they really shouldn’t need supplements,” say doctors at Harvard Medical School.
For those of us who are getting adequate amounts of calcium through our diet, calcium and vitamin D supplements taken in excess can actually do more harm than good. According to a commentary appearing in the Journal of the American Society Nephrology, so-called calcium-alkali syndrome is growing because of widespread use of over-the-counter calcium and vitamin D supplements. Calcium-alkali syndrome refers to dangerously high levels of calcium in the blood, which could cause high blood pressure and even kidney failure. Science Daily reports that Postmenopausal women, pregnant women, transplant recipients, patients with bulimia, and individuals who are on dialysis are at highest risk of developing this syndrome.
So how does the calcium we receive from our diet compare to calcium supplements? A study done by Purdue University found that calcium provided by dairy has an advantage over calcium carbonate (calcium supplements) in promoting bone growth and strength. A study of 300 rats revealed that the rats that were given dairy forms of calcium had stronger, longer, heavier and more dense bones, compared to the rats that were fed calcium carbonate. This is an excellent example of how dietary nutrients are preferable over supplemental forms.
Folate is another example of a nutrient that when taken in excess can impact how our body processes other vitamins. “In adults, supplemental folic acid should not exceed the UL to prevent folic acid from triggering symptoms of vitamin B12 deficiency. It is important to recognize that the UL refers to the amount of synthetic folate (i.e. folic acid) being consumed per day from fortified foods and/or supplements.” says The National Institutes of Health. Most interestingly, there is NO health risk, and NO UL, for natural sources of folate found in food.
To conclude, it is far healthier to obtain our recommended intake of vitamins and minerals from the foods we eat. When this becomes difficult, taking a multivitamin or vitamin supplement is the safest way to ensure we keep nutrient intake at a desirable level. When taken as directed, most multivitamins don’t contain enough of any one vitamin to exceed UL’s.