I have a love-hate relationship with the internet. On one hand, it’s a fantastic way to get great information right at your fingertips (like this article!) On the other hand, it is full of conflicting information – especially about health, and even more specifically about vitamins and supplements. If the internet is your source for information about what supplements you should and should not take, it can get pretty confusing and many of my patients tell me they don’t know where to start. Part of the problem is that there are thousands of supplements on the market – probably hundreds of thousands, maybe even millions. You’ve got your basic types, multivitamins and multiminerals, omega fats, single vitamins like vitamin D, different antioxidants of all types, and a lot of other ones that you may not recognize at all.

As a functional medicine practitioner, I have my informed opinions about the wide range of well-intentioned supplements that I consider to be unnecessary. Oftentimes, any individual really only needs a small handful of targeted vitamins and supplements that will actually be beneficial. Let’s cut through the confusion to determine what supplements can make an actual difference in your health, and how to incorporate them into your existing routine.

Vitamin D.

No other vitamin can hold a candle to vitamin D when it comes to importance and influence on health. Since vitamin D is fat-soluble, it acts more like a hormone than a vitamin by regulating hundreds of uber-important pathways in your body. Besides your thyroid hormones, this vitamin is the only other thing every single cell of your body needs in order to function properly. Also known as the sunshine vitamin, vitamin D is synthesized by your body when your bare skin is exposed to sunlight. It is impossible to get enough vitamin D from food alone, and unless you live in a very sunny place (like near the equator) and are outside frequently without sunscreen, you are probably deficient.

Dosage: If you have had your vitamin D tested by your doctor, you will find that the standard reference range for vitamin D levels falls between 50 and 60 ng/mL. In functional medicine, we aim for an optimal range between 60 and 80 ng/mL. Depending on where your starting levels are, you should be taking anywhere between 2,000 and 6,000 IU of vitamin D per day. Make sure to test your vitamin D levels to find out your starting point, and retest to gauge how your vitamin D level optimization is going. This is a common and easy test and your doctor will likely be fine with it if you ask.

How to incorporate: Since vitamin D is fat-soluble, take advantage of vitamin synergy by combining your supplement with other fat-soluble vitamins, such as A and K2. This will help make it more bioavailable and balanced. It’s also a great idea to take them with fatty foods like avocado, olive oil, wild-caught fish, and coconut to increase their bioavailabiltiy. If you put fats in your daily smoothie (and you should!), this is a good time to pop that vitamin D as well.


Magnesium is a crucial mineral needed for over 300 essential biochemical reactions in your body, including the regulation of neurotransmitters. Up to 80 percent of the population is deficient in this nutrient, and that deficiency can show up as problems with sleep, anxiety, migraines, and brain fog. Most deficiencies come from a poor diet or gut problems that interfere with magnesium absorption.

There are many different forms of magnesium, so let’s break down the best. Magnesium oxide is the most commonly found in supplement form, but it is not nearly as easily absorbed as other forms. Magnesium citrate is a good option, especially if you tend to get constipated. Magnesium glycinate is excellent for its calming effects, and magnesium threonate has shown promise for its neurological support. Magnesium oil is another great way to boost this vital nutrient. You rub it on your skin instead of ingesting it.

Dosage: 350 mg per day.

How to incorporate: Taking magnesium right before bed is often best as it promotes better sleep by relaxing muscles and helping boost levels of the calming neurotransmitter, GABA, in your brain.


As Hippocrates said, “All disease begins in the gut.” Science is finally catching up, with research showing that the gut is the foundation for almost all aspects of your health – regardless of whether you are having digestive symptoms or not. Your gut microbiome contains trillions of bacteria, many of which are beneficial to human health, and some which can cause health problems. When the bad guys start to outnumber the good guys, it can affect everything from your weight to your hormones. While it is important to be including probiotic-rich foods into your diet (give kefir, sauerkraut, kimchi, and kombucha a try). Depending on your level of gut permeability, you may need an additional boost from a probiotic supplement.

Dosage: At least 10 billion CFU per day.

How to incorporate: Feed the probiotics you are trying to grow with prebiotic foods rich in fiber, especially garlic, asparagus, and onions. These foods help facilitate the growth of good gut bacteria. When choosing a probiotic, make sure to take on that includes strains of Lactobacillus and Bifidobacterium. These two specific strains have been shown to reduce inflammation. I am also a fan of soil-based probiotics (SBO) to further support rich bacterial diversity.

Omega-3 fish oil.

Your brain itself is comprised of about 60 percent fat, so depriving your body of fat can contribute to all kinds of unpleasant brain symptoms, from brain fog and fatigue to depression and anxiety. In other words, healthy fat is essential for optimal brain health. If you’re not getting enough healthy fats, specifically from wild-caught seafood, you might want to consider an omega-3 fish oil supplement. Omega fats can be found in plant sources such as flax, but it’s not easily used by our bodies because it must be converted into DHA or EPA, which is an inefficient process. Because of this, I suggest getting your omega fats from krill oil, or fish oil from salmon, cod liver, or sardines.

Dosage: 2250 mg EPA / 750 mg DHA per day.

How to incorporate: If you’re eating more omega-6 fatty acids (like those found in many types of vegetable oils, you may be suffering from increased inflammation. Fish oil may noticeably reduce these inflammatory effects.


Think of this blue-green algae as your superfood of the sea. Spirulina is a great source of iron, phytonutrients, and iodine, all commonly lacking in the modern Western diet.

Dosage: 3 grams per day.

How to incorporate: Spirulina is most commonly available in powder form, which makes it perfect to just stir into your tea or add to your daily smoothie!

To reduce the number of supplements you take, many of those mentioned in this article can be found combined in a single supplement capsule, but watch the dosages, take what feels right and doesn’t upset your stomach, and remember that food is always the best medicine. You can’t supplement your way out of a poor diet. Also, it’s always important to take your individual needs and health case into consideration. Working with a functional medicine practitioner can help you determine what exactly you are lacking to determine what you should be supplementing with.
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