Overwhelmed by the supplement aisle? Here's what your body needs

Q: Every time I walk into my local health food store, the supplements section overwhelms me! It's not just the sheer number, but also the different types of the same vitamin or supplement. How do I know which to buy? Are all forms of a vitamin created equal?

A: I feel your pain. Even with my Ph.D. in nutrition, shopping for supplements can still overwhelm me. Generally speaking most supplements are created equal (vitamin C is vitamin C), but there are several important exceptions to note. Here, five supplements that can be especially confusing and how to pick the best bottle for you.

Fish Oil


Your doctor might recommend prescription-strength fish oil to help treat high triglycerides (a major risk factor for heart disease), but here's something you should know: You can get the same effect from high-potency fish oil sold over the counter-without the steep prescription price. While prescription fish oil is molecularly different than over-the-counter fish oil, that doesn't mean it's better. In fact, according to recent research published in the European Journal of Clinical Nutrition and Prostaglandins, Leukotrienes and Essential Fatty Acids, the body absorbs ‘traditional' fish oil supplements better than the prescription version.

The best buy: To get the biggest bang for your buck, look for a molecularly distilled fish oil supplement that is at least 50 percent pure (meaning that on the nutrition label, the milligrams of EPA and DHA comprise at least half of the total fat in the supplement).

Vitamin D


Vitamin D is a complex nutrient. It's both a vitamin and a hormone that you get from the sun and from food. Additionally, vitamin D supplements come in two forms:

1. Vitamin D2, which is derived from plants that have been exposed to UV light.

2. Vitamin D3, which is the form of vitamin D that you get from sunlight and from eating fish.

For decades these two forms of vitamin D have been considered equally effective, but scientists now know that vitamin D2 supplements are inferior compared to vitamin D3.

The best buy: Unfortunately vitamin D2 has been the standard go-to form of vitamin D for many multivitamin manufacturers. To maximize your uptake of this extremely important vitamin, check the label on your multivitamin and make sure it includes vitamin D3 (also known as cholecalciferol).



Magnesium powers more than 300 different reactions in your body and is a key player in overall health. Because it's sold in multiple forms-magnesium oxide, magnesium sulfate, magnesium carbonate, etc.-it's also one of the more confusing supplements to purchase. Magnesium oxide is often touted as the best choice since it contains the highest amount of the actual mineral, but in reality it's absorbed the worst.

The best buy: Look for chelated (I like magnesium malate) or topical magnesium. Topical magnesium can be rubbed behind your knees prior to bed to give you the added benefit of promoting muscle relaxation and helping you sleep.



I've covered the different levels of calcium in milk and milk alternatives in the past, but diet alone often isn't enough to meet the daily recommended intake of calcium (1000mg/day for women ages 19-70). Like magnesium, calcium comes in several different forms, each one containing different levels of actual calcium.

The best buy: Dosage is the most important factor here. Make sure to check the nutrition facts label to see how much calcium you're actually getting and only supplement with 500mg at any given time, spreading your 500mg doses throughout the day until you hit your calcium target.

Vitamin A


Unlike most popular vitamins, vitamin A poses a serious toxicity risk. Fortunately the health risks associated with taking in too much vitamin A (headaches, hair loss, and blurred vision) can easily be avoided if you pick the right supplement.

The best buy: Any supplemental vitamin A you take should be "pro-vitamin A." Pro-vitamin A, also known as a group of compounds called provitamin A carotenoids (the most popular being beta-carotene), do not pose a toxicity risk. The body converts them to vitamin A as needed, allowing you to reap additional benefits of carotenoids such as reducing risk of breast cancer and improving heart health.