Ever wonder when you should be taking your supplements? Should I take with food? Do they interact with each other?

I get asked these questions all the time from my clients. Here is a timing guide to take the guesswork out of when to take and how to get the most absorption out of your supplementation.

In general take supplements with a meal containing fat for best absorption and least stomach irritation, especially important for the fat-soluble vitamins (A, D, E and K). Many vitamins and mineral supplements can cause nausea, heartburn and other intestinal issues, especially when taken on an empty stomach. Follow the guidelines from your practitioner or Doctor. Take as recommended per the bottle’s instructions. Some supplements may interact with prescription medications. Read labels carefully and speak with a Dr. if you have any concerns.

Vitamin D
Vitamin D is fat-soluble which means it is best to be taken with your largest meal that contains fat. Could be anytime during the day or night.

Needs to be taken with food to avoid stomach upset. Should NOT be taken with a Calcium or Iron supplement to ensure proper absorption of Zinc.

Iron is best taken on an empty stomach. Do Not take with Calcium ,vitamin E or Fiber, these nutrients interfere with Iron absorption. Iron is more absorbable when paired with citrus.

Vitamin C
Vitamin C is water soluble which means it lasts only a few hours in the bloodstream. Does not need to be taken with food. Dosage can be broken up throughout the day to support your system. Vitamin C is beneficial if you are not getting your daily dose of fruits and vegetables.

One of our most important minerals. Best taken on an empty stomach, at night but can also be taken with food during the day if you are splitting up your dosage. It helps the body relax, if you are taking calcium, take together. Magnesium increases GABA, which encourages relaxation as well as sleep. Magnesium also plays a key role in regulating the body’s stress-response system. There are many types of Magnesium, speak to your practitioner to get the one that meets your specific needs.

Take first thing in the morning or just before bedtime with a FULL glass of water. Start with a small amount to see how you tolerate it. Water is vital when taking supplemental fiber.

Vitamin B-12
B12, which tends to be poorly absorbed no matter what, is best taken on an empty stomach to optimize absorption and in the morning.

These works specifically with our microbiome. Best to follow practitioners/Doctor’s recommendation or the packaging label. Some are best on an empty stomach and some work best after a meal. Do not take within 4 hours of taking antibiotics.

Digestive enzymes
Take on an empty stomach, just before eating.

Take with a meal. If you’re on blood-thinning medication, consult with a physician as high doses may increase the risk of bleeding.


Karen Ellis is Functional Nutrition Specialist with 20 years of experience in the health and wellness industry. Her passion for a holistic approach to health came after a weight loss pill caused me to have a stroke and open-heart surgery at the age of 35.

With the unexpected death of my husband and the complexities of my own health issues, my well-being was paramount as a single mother of two young boys.

I am a Functional Medicine Practitioner through The School of Applied Functional Medicine. My health coaching training and certification is from Columbia University for the Institute of Integrative Nutrition in New York. I am board certified by the American Association of Drugless Practitioners. I also hold a B.S. in Psychology from the New York Institute of Technology and I’m  a classically trained raw and whole foods chef from Lincoln Culinary School.