Vitamin and mineral supplements are a good thing. But too much of a good thing can negate any health benefits — and even pose health risks.
Why it matters: Calcium plays a critical role in building and maintaining healthy bones. For decades, experts have recommended high-dose calcium supplements to prevent osteoporosis. The bone-thinning disease is responsible for fractures that cause many elderly men and women to lose their independence — and sometimes their lives.
How too much can hurt: “More and more studies are showing increased risks for heart attack and stroke among men and women taking calcium 1,000 to 1,200 milligrams (mg) per day as directed,” says Dr. Young.
Researchers believe that without adequate vitamin D to help absorb it, the extra calcium settles in the arteries instead of the bones. There, it helps form plaques that threaten the heart and brain. Excess calcium can also cause muscle pain, mood disorders, abdominal pain and kidney stones.
What to do about it: “We recommend trying to get your calcium from food,” says Dr. Young. “The body absorbs and utilizes calcium better from food than from supplements.”
Probably the best source of dietary calcium is fat-free organic Greek yogurt. It gives you 450 mm of calcium per serving, plus vitamin D and protein, and two servings fulfill your calcium needs for a full day. Other sources of calcium include:
- Leafy green veggies like spinach and kale
- Legumes and beans
- Fortified foods, like soy and almond milk, orange juice, and
- Salmon with soft bones
- Sesame seed
2. Vitamin D
Why it matters: Vitamin D works in tandem with calcium to fortify your bones, and research shows it improves asthma and depression. Vitamin D also strengthens the immune system and boosts immunity.
Your skin manufactures the vitamin after exposure to the sun’s ultraviolet rays. “Yet we are an indoor society and, unlike our ancestors, we wear clothing (and sunscreen) when we go outdoors,” says Dr. Young.
Most Americans are deficient in vitamin D and have blood levels in the 20s. So most doctors recommend vitamin D supplements to bring blood levels up to 30 ng/mL. “Past studies have suggested improved benefits when vitamin D levels are closer to 50 ng/mL, so that is our target in the Center for Integrative Medicine,” says Dr. Young.
New studies question the benefits of vitamin D supplements for prevention and survival from diseases. However, “in the Center for Integrative Medicine, we see significant improvement in patients’ pain, mood and quality of life with vitamin D supplements,” says Dr. Young.
How too much can hurt: Vitamin D blood levels exceeding 100 ng/mL can be dangerous. The extra vitamin D triggers extra calcium absorption. This can cause muscle pain, mood disorders, abdominal pain and kidney stones. It may also increase risk for heart attack and stroke.
“Most reports of toxicity involve patients taking synthetic vitamin D2, so we prescribe natural vitamin D3,” says Dr. Young.
What to do about it: “We recommend starting with a simple blood test to determine your levels of vitamin D, and then prescribing vitamin D3 supplements,” says Dr. Young. You should see your doctor every three months until you reach steady vitamin D blood levels. That usually takes six to 12 months. After that, checkups every year or every other year are fine.
3. Vitamin A
Why it matters: Vitamin A is important for visual health. It also contributes to healthy skin and hair, and boosts your immunity. Signs of deficiency include night blindness, dry, scaly skin around your eyes, coarse hair and respiratory infections.
How too much can hurt: Fat-soluble vitamins like vitamin A can lead to toxicity because the body stores any excess in fat and does not excrete it. Two signs of vitamin A toxicity are headache and skin rashes. Research also suggests that extra vitamin A may work against vitamin D and cause osteoporosis.
Vitamin A’s presence in so many different supplements compounds the problem. “Patients who take a variety of supplements are getting much more vitamin A than they should,” says Dr. Young. “We recommend no more than 5,000 international units (IU) per day from both supplements and your diet long-term.”
She does not recommend cod liver oil; it has pre-formed vitamin A that can lead to toxicity.
What to do about it: It’s better to get vitamin A from orange-colored vegetables and fruit — carrots, sweet potatoes, squash and papayas. Dark green, leafy vegetables and egg yolks are also good dietary sources of A.
The bottom line
It’s important to get as many vitamins and nutrients as you can from your food. “However, widespread changes in farming practices mean a lower nutrient content in our fruits and vegetables,” cautions Dr. Young. “Many people still benefit from their nutrient levels assessed and taking a high-quality daily multivitamin.”