Are You Taking Too Much Calcium or Vitamin A or D?

Overdoing supplements can hurt you
Illustration of the human body depicting skeleton and circulatory systems overlayed on various pills in background

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.

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With calcium, vitamin A and vitamin D, “more is not necessarily better,” cautions functional medicine specialist Melissa Young, MD.

1. Calcium

Why it matters: Calcium plays a critical role in building and maintaining healthy bones. Benefits may also include weight loss, and reducing colon cancer risk. For decades, experts have recommended calcium supplements to prevent osteoporosis which 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 which was previously recommended,” 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 obtaining the majority your calcium needs from food,” says Dr. Young. “The body absorbs and utilizes calcium better from food than from supplements.”

If you are not sensitive to dairy, a good source of dietary calcium is grass fed, organic Greek yogurt. It gives you 450 mg of calcium per serving, plus vitamin D and protein. Two servings fulfill your calcium needs for a full day. Additional highly absorbable sources of calcium include:

  • Leafy green veggies like spinach and kale.
  • Legumes and beans.
  • Sardines.
  • Fortified foods, like soy and almond milk, orange juice.
  • Salmon with soft bones.
  • Sesame seeds.

It is often not enough to obtain adequate intake of calcium for optimal bone health but to also prevent loss of calcium from the body. Don’t forget to the following:

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  • Avoid excess sodium (salt) intake.
  • Avoid smoking .
  • Obtain a significant portion of your dietary intake of calcium from plant-based foods.

2. Vitamin D

Why it matters:  Vitamin D is a fat-soluble vitamin that promotes the absorption of calcium, regulates bone growth and plays a role in immune function. It 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 may boost mood and an overall sense of well-being.

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.

Many Americans are deficient in vitamin D and have blood levels in the 20s. Most doctors recommend vitamin D supplements to bring blood levels up to at least 30 ng/mL. “Past studies have suggested improved benefits when vitamin D levels are closer to 50 ng/mL.

Newer studies question the benefits of vitamin D supplements for prevention and survival from diseases. However, “at the Center for Functional Medicine, we see significant improvement in patients’ pain, mood and quality of life with vitamin D supplementation,” 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 studies show that vitamin D3 is more effective than vitamin D2 at raising blood levels of calcifediol, the main circulating form of vitamin D. “I recommend Vitamin D3 supplementation to patients whenever possible,” says Dr. Young.

What to do about it:  “We recommend starting with a simple blood test to determine your levels of 25-hydroxyvitamin 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.

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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.

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 15,000 international units (IU) per day of mixed carotenes.

What to do about it:  It’s better to get vitamin A from carotenoid-containing fruits and vegetables. In addition to orange-colored vegetables and fruit — carrots, sweet potatoes, squash and papayas, you need lycopene, astaxanthin, zeaxanthin and lutein found in red, and yellow-orange fruits and vegetables as well as leafy greens, eggs, shrimp and salmon. And don’t forget watermelon, guava, pink grapefruit and tomatoes.

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 having their nutrient levels assessed and taking a high-quality daily multivitamin.”

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