How Many Vitamins Can You Actually Absorb?

A dietitian explains how many vitamins you should be getting every day, and where to find them.

vitamins

Have you ever wondered if you can rid yourself of a cold in a single day by consuming copious amounts of vitamin C? Us too. The unfortunate answer, according to Liz Weinandy, resident dietitian at The Ohio State University Wexner Medical Center, is probably not—your body won’t absorb much more than the recommended daily doses of vitamins provided by dietary officials (we’ll get to those later). Any excess just ends up being flushed down the drain.

“Exactly how much of any vitamin or mineral our body can absorb per day depends on both the person and the actual vitamin and mineral,” Weinandy says. She encourages looking more into where we’re getting our vitamins from, rather than how much you can can absorb, and this depends on a ton of different variables. “The vitamins and nutrients you receive from food are much better absorbed because they’re being absorbed in tandem with every other vitamin, mineral and compound within that food,” she says, noting that vitamins in pill form—which aren’t accompanied by other substances—don’t absorb as well (this is also why doctors recommend taking pills with a meal).

This brings us to an interesting point: Although the vitamin and supplement industry is projected to bring in $36 billion in 2017, for the most part, taking vitamin pills is a waste of your time, if you’re eating right. A 2013 paper in the Annals of Internal Medicine concluded (with an exasperated “Enough is enough” sign off) that “there was no clear evidence of a beneficial effect of supplements on all-cause mortality, cardiovascular disease or cancer.”

This might be surprising, considering health food stores and supplement websites seem to carry a vitamin for every kind of man: There’s one for the guy looking to lose weight; for the man over 50; for the regular guy who just needs a health boost; for the man who wants more hair; and the man who wants help getting it up. Impressive product diversity, considering each pill is apparently more or less irrelevant.

And to clear up any possible confusion: Yes, you do need vitamins. They’re key organic components that keep you alive and healthy, and if you don’t get your daily doses, your bone and oral health will diminish, your immune system will shut down and you’ll experience chronic fatigue—all symptoms of being malnourished. But we’re not scurvy-ridden 13th century pirates without access to citrus fruit (and their vitamin C)—unless you’re a nutritional outlier, almost all of your basic vitamin requirements are already satisfied by what you eat. As Weinandy points out, the key to making sure you’re getting all the vitamins you need to stay healthy is ridiculously simple: Eat right. Target all five food groups, especially whole veggies and fruits.

As the breakdown below illustrates, for most vitamins, it doesn’t take much: A handful of sunflower seeds (vitamin B1) or a can of tuna (vitamin B12). In the rare case that it’s hard to get it easily from foods, like vitamin D, simply supplement with more food—especially fish, which is loaded with vitamin D. Pretty much any breakfast cereal is fortified with vitamins and minerals (though, like pills, these vitamins and minerals are added from concentrate, so they’re not quite as good as the real deal).

DAILY DOSE

Here’s how much of each vitamin you actually need per day:

Vitamin A
For: Good vision and possibly reducing the risk of prostate cancer.
Found in: Beef, liver, eggs, carrots and sweet potatoes.
Recommended dose: 900 micrograms/day, which can roughly be found in two medium carrots.

Vitamin B1 (Thiamin)
For: Healthy hair, skin, nails, muscles and brain.
Found in: Ham, sunflower seeds and watermelons.
Recommended dose: 1.2 milligrams/day, which can be found in 3 ½ ounces (or a big handful) of sunflower seeds.

Vitamin B3 (Niacin)
For: Healthy skin, blood cells, brain and nervous system.
Found in: Meat, poultry, beets, fish, whole grains, mushrooms and peanuts.
Recommended dose: 20 milligrams/day, which can be found in a five-ounce chicken breast.

Vitamin B12
For: Helps protect nerve cells, helps make red blood cells, might also lower risk of heart disease.
Found in: Meat, poultry, milk, cheese and fortified breakfast cereals.
Recommended dose: 2.4 micrograms/day, which can be found in less than an ounce of canned tuna.

Vitamin C
For: Helps protect cells from damage, improves absorption of iron and helps the body make collagen, a protein required to heal wounds.
Found in: Citrus fruits, juices, potatoes, broccoli, spinach and tomatoes.
Recommended dose: 90 milligrams/day, which can be found in one medium orange.

Vitamin D
For: Acts as an antioxidant, protects cells, might help prevent Alzheimer’s and prostate cancer.
Found in: Dairy, fortified breakfast cereal, fatty fish, beef liver, eggs and leafy green vegetables.
Recommended dose: 15 micrograms/day, which can be found in 3 ounces of cooked salmon. Although you can also get most of the Vitamin D you need from exposure to sunlightyou only need to expose your skin for around half the time it would normally take to start to burn to produce more than enough vitamin D for one day.

Calcium
For: Bone and teeth health. Helps with blood clotting and muscle contractions and helps maintain healthy blood pressure.
Found in: Although everyone thinks of milk as the go-to source of calcium, it’s actually doing more harm to your bones than good. Dairy products (including cheese and yogurt) can be high in saturated fat and retinol (vitamin A), which at high levels can weaken the bones by triggering an increase in osteoclasts (the cells that break down bone tissue). Instead, try non-dairy sources of calcium, which include tofu, salmon, broccoli, kale, collard greens, bok choy, fortified soy milk and baked beans.
Recommended dose: 1,000 milligrams/day, which can be found in three eight-ounce glasses of calcium fortified soy milk.

Iron
For: Helps hemoglobin in red blood cells and helps the body make amino acids, collagen, neurotransmitters and hormones.
Found in: Lean red meat, poultry, fish, oysters, beans, lentils, broccoli, dark chocolate and fortified breakfast cereal.
Recommended dose: 8 milligrams/day, which can be found in 2 ½ cups of white beans.

Zinc
For: Needed for immune system health, taste, smell and wound healing.
Found in: Red meat, poultry and oysters.
Recommended dose: 11 milligrams/day, which can be found in six ounces of beef chuck.

If you think you’re nutritionally deficient—which you probably aren’t if you eat even vaguely healthily—then go see your doctor. A blood test will determine what your body is lacking. If you do a have a deficiency, you’ll most likely be prescribed a dose of a specific vitamin to make up for whatever you’re not getting enough of from the food you eat. Or, your doctor might just tell you to round out your diet. Eat your veggies, people!