Supplement FAQs

I get asked about supplements (nearly) every hour of every day. So here’s my elevator pitch for every one.

This list will expand over time.

Vitamins

• Vitamin A - Has two common forms: preformed (sometimes called retinoid or retinol) comes from animals, while carotenoids come from vegetables.
  • It’s good for vision, cellular growth/reproduction/differentiation, bone development and your immune system.
  • Typically less than 10% of carotenoids turn into retinol, so if you’re vegan you probably need a mountain of veggies every day to get enough vitamin A, which can be bad (see below).
  • Too much Vitamin A disrupts Vitamin K absorption. Carotenoids in particular can decrease plasma Vitamin E.
  • Harrison’s verdict: If you eat beef every other day and colorful veggies every day you probably don’t ever need to think about Vitamin A. If you take tons of cod/fish liver oil supplements then you can justifiably be concerned about Vitamin A toxicity.

• Vitamin B - Is actually a whole host of vitamins, most of which you never need to think about unless you are vegan or hardcore vegetarian. 
  • They’re good because they are fundamental to most metabolic processes and energy production. 
  • Most B vitamins are so common you probably cover your daily needs just by thinking about food (I kid).
  • Too much Vitamin B… basically does not exist. It is not stored well in the body and is excreted in urine, so you need them literally every day.
  • Harrison’s Verdict: B12 is the only interesting one. Vegans and vegetarians probably need to supplement with this because the B12 in vegetarian foods is commonly only there because of cross contamination from animal sources, such as feces and other bacteria (you’re welcome).

• Vitamin C - One sexy vitamin. Everyone knows you need it, but there actually is too much of a good thing.
  • It’s an anti-oxidant and keeps inflammation low = good stuff for the immune system. As an anti-oxidant it’s a reducing agent for other chemical processes, making it fundamental for connective tissue health (collagen production depends on it, for example).
  • Fruit is the most common source of vitamin C, also deep green veggies and green bell peppers.
  • Too much Vitamin C can likely slow muscle growth and strength development though (at least if you have it Vitamin E). Muscle grows because of healthy inflammation, so too much Vitamin C slows muscle growth. 
  • Harrison’s verdict: If you eat even a handful of the obvious fruits or the veggies above, you’re good for the day, no matter who you are.

 

• Vitamin D - The Mighty D. Food sources of it are laughably low and you should laugh at anyone who says they can eat their way to healthy levels of it. Almost no-one is getting enough of it, even plenty of leathery sun worshippers.
  • It’s pivotal to bone strength, immune and neuromuscular function, and testosterone synthesis (important even for women of all ages). Healthy levels of Vitamin D even influence how strong you can actually become.
  • Most people have laughably low levels of it, even those who think they’re healthy (like people who exercise outside regularly).
  • Your body is designed to hold utterly massive doses of Vitamin D at once., and it does an incredible job of regulating it. Your body will place it in storage for later, or even destroy excess amounts if necessary.
  • The darker your skin, the more sun exposure you need to hit your dose. Fair skinned people need less. Cloud cover, bodyweight, diet, UVA/UVA ratios, and even latitude factor into how much you’ll absorb per minute.
  • Harrison’s verdict: Are you pasty and spend less than 20 minutes outside (naked) each day? Are you dark and spend less than 45 minutes outside (naked) every day? Then supplementing is probably a good idea.

 

• Vitamin E - Actually 8 different isoforms with different functions, involved mostly in cellular membrane health. Like Vitamin C too much of it can be bad for your muscle.
  • Nearly all Vitamin E/multivitamin supplements contain only one of these isoforms. So they actually are likely to cause overall Vitamin E deficiency due to over-supplementing one form which blocks the other forms from getting absorbed. And as a bonus, synthetic Vitamin E is 26% less absorbable than Vitamin E from real food, so you get to pay for the privilege of cellular membrane deficiency. 
  • Too much Vitamin E can reduce muscle growth due to overly vigilant inflammation suppression. 
  • Nuts contain a lot of Vitamin E, which is a shame because nuts are so packed with anti-nutrients that block the absorption of other vitamins and minerals that they’re probably not a smart thing to eat every day. Plus they're super fatty and make me eat the whole bag.
  • Harrison’s verdict: Spinach and broccoli are likely the best vegetable sources of Vitamin E, so get your Popeye on.

 

• Vitamin K - Two natural forms: K1 which comes mostly from plants, and K2 which comes mostly from bacteria in things like cheese etc (within K2, MK-4 and MK-7 are the most common variants). Your gut bacteria actually can create some Vitamin K activity, but its usually not enough to cover your daily needs.
  • Vitamin K is important for blood coagulation (so you bruise less easily and can heal wounds faster). It’s also involved with bone formation, working alongside Vitamin D and calcium. 
  • Too much Vitamin K is rare. Your body does'nt hold on to it well (even though it’s fat, not water, soluble), so eating it daily is usually your best bet.
  • Your body can convert K1 to K2, nevertheless it’s eating K2 that’s more closely associated with health than eating K1.
  • Dark green, leafy veggies are the most common source of K1, while most people get their K2 from fermented foods (sauerkraut, some cheeses, etc.)
  • Harrison’s verdict: unless you’re eating 2 whole avocados (that’s a lot of calories), 3 cups of blueberries (that’s a lot of carbs for some people), or a bowl full of sauerkraut or kimchi (that's a lot of hot breath) every day, supplementing with K2 can be a good idea 

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