Walk down the supplement aisle of any health food store, and you'll quickly become overwhelmed. There are vitamins, minerals, herbs, probiotics, powders, gummies, and promises of better health around every corner.
So how do you know what your body actually needs?
As a nutritionist, I always remind people of one important principle:
Food comes first. Supplements come second.
A nutrient-rich diet built around whole, minimally processed foods should always be the foundation of good health. But even with the best intentions, supplements can sometimes help fill nutritional gaps.
The key is understanding why you're taking them, when to take them, and how to maximize their absorption.
Why Take Supplements?
Supplements are exactly what their name implies—they are meant to supplement your diet, not replace it.
There are many reasons someone may benefit from supplementation, including:
Limited intake of certain foods
Poor nutrient absorption due to digestive conditions
Certain medications that interfere with nutrient absorption
Aging, which naturally reduces absorption of some vitamins
Pregnancy or breastfeeding
Living in northern climates with limited sunlight
Following restrictive diets
Laboratory-confirmed nutrient deficiencies
Rather than taking supplements "just because," it's always best to discuss your needs with your healthcare provider and, when appropriate, use lab work to guide your decisions.
Water-Soluble vs. Fat-Soluble Vitamins
Not all vitamins behave the same way.
Water-Soluble Vitamins
These include:
Vitamin C
B-complex vitamins (B1, B2, B3, B5, B6, B7, B9, and B12)
Because they dissolve in water, your body doesn't store large amounts of them. Any excess is generally excreted in urine.
These vitamins are often best taken earlier in the day, preferably with a meal. Some B vitamins may increase alertness, so taking them in the morning works well for many people.
Fat-Soluble Vitamins
These include:
Vitamin A
Vitamin D
Vitamin E
Vitamin K
These vitamins require dietary fat for optimal absorption.
Taking them with a meal that contains healthy fats—such as avocado, nuts, seeds, olive oil, or nut butter—can improve how well your body absorbs them.
What About Magnesium?
Magnesium has become one of my favorite minerals to discuss because it participates in hundreds of enzymatic reactions throughout the body.
It supports:
Muscle relaxation
Healthy nerve function
Blood sugar regulation
Bone health
Energy production
Heart health
Many people also find that magnesium taken in the evening helps promote relaxation and supports better sleep. While research suggests magnesium may improve sleep quality in people who are deficient or have certain sleep concerns, it is not a guaranteed sleep aid for everyone.
If you take both magnesium and a fat-soluble vitamin like vitamin D, many people find that taking them together with dinner or an evening meal containing healthy fats is both convenient and supports good absorption.
Different forms of magnesium have different purposes. For example:
Magnesium glycinate is commonly chosen for relaxation and sleep because it tends to be gentle on the stomach.
Magnesium citrate may be more helpful for occasional constipation because it draws water into the intestines.
Common Nutrients That Can Be Low
While everyone's needs are different, research suggests several nutrients are commonly consumed in amounts below recommended levels or are frequently found to be low in blood testing.
These include:
Vitamin D
Magnesium
Vitamin B12 (particularly in older adults and those following vegan or vegetarian diets)
Iron (especially among menstruating women, though supplementation should only be guided by testing)
Calcium (often due to low intake rather than true deficiency)
Omega-3 fatty acids (EPA and DHA)
Remember, low dietary intake isn't the same as a medical deficiency. Blood work and an individual's health history provide a much clearer picture than assumptions alone.
A Few Tips for Better Supplement Absorption
Here are a few simple guidelines:
✔ Take fat-soluble vitamins with a meal that contains healthy fat.
✔ Take water-soluble vitamins with food if they upset your stomach.
✔ Separate iron from calcium supplements, as calcium can reduce iron absorption.
✔ Pair iron-rich foods or iron supplements with vitamin C to improve absorption.
✔ Always follow dosage recommendations unless instructed otherwise by your healthcare provider.
Food Still Wins
Supplements can certainly play an important role in supporting health, but they can never replace the thousands of beneficial compounds found naturally in whole foods.
A colorful plate filled with vegetables, fruits, whole grains, beans, lentils, nuts, and seeds provides vitamins, minerals, fiber, antioxidants, and phytochemicals that work together in ways a single supplement simply cannot replicate.
Supplements are tools—not magic pills.
When used thoughtfully and alongside a healthy lifestyle, they can help fill gaps and support overall wellness. But the greatest investment you can make in your health will always begin with what you put on your plate.
To Health & Longevity, 🌿
Innovative Wellness
References
National Institutes of Health, Office of Dietary Supplements. Dietary Supplement Fact Sheets.
Institute of Medicine. Dietary Reference Intakes.
Harvard T.H. Chan School of Public Health. The Nutrition Source: Vitamins and Minerals.
National Institutes of Health. Vitamin D Fact Sheet for Consumers.
National Institutes of Health. Magnesium Fact Sheet for Consumers.
DiNicolantonio, J. J., O'Keefe, J. H., & Wilson, W. (2018). Subclinical magnesium deficiency: A principal driver of cardiovascular disease and a public health crisis. Open Heart.