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How to Plan Your Dietary Supplement Regimen

"Should I take it in the morning or at night?”

“Should I take this with or without foods?”

“Can I take this with that?”

As a practicing Registered Dietitian, these are the questions that are often brought up by my patients when it comes to taking dietary supplements. In the United States, 52% of Americans are taking or has taken dietary supplements before. While the need of taking dietary supplement is still of debate for an average healthy individual, dietary supplements are sometimes recommended for people with specific medical conditions, nutrient deficiencies, or for those with food allergies or follow a special diet . For example, a pregnant women should take folic acid to decrease risk of neural tube defects for the unborn, and vegans can take a vitamin B12 supplement because their food choices are restricted from such nutrient from animal foods.

According to the 2015 Dietary Guidelines for Americans, “Nutritional needs should be met primarily from foods.” I believe one should eat a nutritious and well-rounded diet that includes all five food groups (grains, protein, low fat dairy, vegetables and fruits) and a variety of different foods to meet their nutrient needs. Dietary supplements can then be used in complementary to a healthy and balanced diet to meet certain nutrient needs, especially for known nutrient deficiencies. If you are taking or planning to take any dietary supplements, this article can help you design the best supplement regimen for optimal absorption.

Morning or night?

  • Multivitamins and B vitamins in the morning

B vitamins can help with energy production. So don’t be surprised if you have trouble falling asleep after taking your B vitamins at night. This also applies to multivitamins which contains the B vitamins. To avoid this, take them in the morning for best efficacy.

  • Probiotics at night

If you are new to taking probiotics, you might experience gassiness after taking it. This is especially true when you take prebiotics with your probiotics. I suggest taking your probiotics at night so that you can sleep through this unpleasant feeling. However, it should go away after a few weeks of consistent probiotics regimen as your gut microbiome becomes more balanced.

With or without foods?

  • Multivitamins and Fat-soluble vitamins with a meal that contains fat

Fat-soluble vitamins, including vitamin A, D, E and K, are better absorbed when taken with a meal that contains at least a teaspoon or 5 grams of fat. This applies to Multivitamins which also contains these fat-soluble vitamins. So enjoy eating your salad with some salad dressing topped with some nuts and seeds or even avocado if you are taking these supplements with it.

  • Chelated mineral supplements without foods

While many minerals need stomach acid for digestion and absorption, chelated ones do not. Chelation refers to when a mineral has been bound to an acid to aid absorption, so chelated mineral supplements can be taken without foods. Calcium citrate or chelated iron are good examples.

  • Probiotics with fiber rich meals with some fat

A study published in the journal Beneficial Microbes found that probiotics taken 30 min before meals or even within 30 minutes of eating something, survived in much higher numbers than those taken 30 minutes after a meal. This is because the gut environment becomes more suitable for the survival of probiotics when eating foods. This study also suggests the survival of probiotics is higher when taken with foods that contains some fat.

Take together

  • Calcium with Vitamin D

  • Iron with Vitamin C

These nutrient combinations are better taken together as vitamin D enhances calcium absorption and vitamin C enhances iron absorptions. This is why you see these combinations in one single supplement. You may also take iron when eating a vitamin C rich foods for the same benefit, such as an orange or some berries.

Take separately

  • Separate calcium from iron and multivitamin

Calcium affects the absorption of iron, zinc, and magnesium, which are also found in the multivitamin. I suggest separating calcium supplement from multivitamin or any individual supplement of these minerals by at least 2 hours for optimal absorption. On the other hand, taking less than 500 mg of calcium at a time also makes it better absorbed in the body.

  • Separate fiber supplement from other vitamins or mineral supplements

Fiber supplement affects the absorption of many vitamin supplements. If you are not taking anything else at bedtime, I suggest taking fiber supplement then.

Whether you are taking dietary supplement or not, it is not intended to substitute whole foods. And you may be better off just focusing on eating nutritious whole foods and balanced meals, because science suggests that this, rather than supplements, is the optimal way to get your nutrients. If you experience any symptoms that may be related to any nutrient deficiency, consult with your doctor or a registered dietitian.

Interested in learning about weight goal and nutrition needs? Schedule a free body weight and % body fat analysis with Our Smart Eater Dietitians at 626-283-5128 or email to

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