Vitamin D and other vitamins and minerals


The way that vitamins and minerals work in your body is interconnected. How well vitamin D works depends on the amount of other vitamins and minerals that are present in your body. The other vitamins and minerals needed to help vitamin D work well are called cofactors.

To get the most benefit from vitamin D, you must have other cofactors in your body. Vitamin D has a number of cofactors; the ones listed below are the most important.

  • Magnesium
  • Vitamin K
  • Zinc
  • Boron
  • Vitamin A

Doctors and scientists are still working to understand fully how different vitamins and minerals work together in your body, and how that affects your health.

The Food and Nutrition Board in the United States sets Recommended Dietary Allowances (RDA) for the amount of some vitamins and minerals.  These tell you the amount you need to take every day to stay healthy and are different for each vitamin and mineral. If you’re eating a healthy, balanced diet you should be getting most of the vitamins and minerals you need (with the exception of vitamin D!).


You can find magnesium in leafy greens, nuts and seeds.

Your body needs magnesium to help it work properly and efficiently. Every organ in your body needs magnesium to work properly and it’s a key part of the process that turns the food you eat into the energy your body needs. Magnesium is important for functions such as controlling your blood pressure and blood sugar levels and keeping your heart beating regularly.

Magnesium helps your body to use vitamins and other minerals, such as calcium, phosphorus, sodium, potassium, and vitamin D.

You can get good amounts of magnesium from foods such as leafy green vegetables like spinach, nuts and seeds, and whole grains (wheat germ or bran).You can also get magnesium by taking magnesium supplements. However, many people in the United States probably don’t get enough magnesium from the foods they eat. African Americans and other ethnic groups are more likely to be lacking in magnesium than white Americans.

What we say

The Vitamin D Council believes that the daily amounts of magnesium recommended by the Food and Nutrition Board aren’t enough to keep your body healthy; and that both men and women may need more than is recommended.  Some research studies show that your body needs between 500 and 700 mg a day.

Magnesium may help vitamin D by helping your body activate vitamin D into a form your body can use, though it’s not known how much is ideal or if not getting enough magnesium harms your ability to fully make activated vitamin D. Also, magnesium is important in helping vitamin D to maintain calcium in the body and is essential for bone health.

If you want to take magnesium, and you’re taking medications or have health problems, check with your physician first. See the Office of Dietary Supplements for more information on magnesium.

Vitamin K

Your body needs vitamin K for two important reasons; to help wounds heal properly, by making sure your blood clots, and to keep your bones strong and healthy. There is also some research which shows that vitamin K may help to protect against developing conditions like heart disease, prostate cancer and Alzheimer’s disease.

Vitamin K is important in making sure that the calcium you get from foods or supplements is used in your bones. Vitamin D and vitamin K work together to strengthen your bones and to help them develop properly.

There are two main types of vitamin K.

  1. Vitamin K1, which comes from leafy green vegetables like kale, chard and spinach.
  2. Vitamin K2, which comes from meats (organ meats in particular, such as liver), eggs, insects and hard cheeses. This type of vitamin K2 is called MK-4. There is also a different kind of vitamin K2, called MK-7, which comes from natto.

Vitamin K can also be taken as a supplement, either as K1 or K2, and the K2 can be either MK-4 or MK-7.

Which type?

Research is still trying to sort it all out, but research is showing that you likely need both vitamin K1 and K2.

The National Academy of Sciences has set Adequate Intake (AI) levels for vitamin K, which is the amount that adults and children need every day.

National Academy of Sciences has set Adequate Intake (AI) levels for vitamin K:
Children under 1 year 2-2.5 mcg
Children 1-3 years 30 mcg
Children 4-13 years 55-60 mcg
Adolescents 14-18 years 75 mcg
Adult men 120 mcg
Adult women 90 mcg
Women who are pregnant or breastfeeding 75-90 mcg

For more information regarding the vitamin K, read our page, “The synergistic relationship between vitamin D and vitamin K.”


If you’re taking blood thinning medicines, such as Warfarin or Coumadin, don’t take vitamin K supplements. This is because it may affect how well your blood clots.


Zinc is important to the body for a variety of reasons.

Zinc is a mineral and it’s found mainly in your muscles and bones. It is important for:

  • fighting infection and healing wounds.
  • helping your body to make new cells and substances called enzymes.
  • helping your body  to use the carbohydrate, fat and protein in food.
  • growth and development  – so it’s vital to get enough during pregnancy, childhood and adolescence.
  • your sense of taste and smell.

You can get zinc from a number of foods. Oysters contain more zinc that any other food, but it’s also found in red meat, poultry, beans, seafood such as crab and lobster and nuts. Some breakfast cereals have zinc added to them.

Much of the zinc we get from foods comes from meat, and the zinc that is found in vegetables and grains is harder for your body to use. This means that if you’re a vegetarian, you may need more zinc every day than people that eat meat. If you’re over the age of 60, you’re also more likely to be lacking in zinc.

Zinc isn’t stored in your body, so you need to eat foods that contain it every day, or take supplements. Supplements are available in a number of different forms, such as tablets and capsules or as part of many multivitamins. Some cold lozenges that contain zinc are also labeled as supplements.

Zinc may help vitamin D to work inside the cells of your body. It’s also important in making sure that the calcium you get from foods or supplements is used in your bones. Vitamin D and zinc work together to strengthen your bones and to help them develop properly.


If you’re taking amiloride, prednisone, cyclosporine or any other medicine that suppresses your immune system (immunosuppressant) you shouldn’t take zinc supplements without talking to your physician first.


Boron is a trace mineral, which means it’s only present in small amounts in your body, and your body only needs small amounts of it to stay healthy. It’s essential for good health and helps your body to use other minerals such as calcium and magnesium properly. It helps to keep your bones healthy, affects how well your brain works and affects the hormone levels in your body, for example your level of testosterone.

You get boron from the foods you eat and from some drinks. Fruit, leafy vegetables and nuts contain good amounts of boron, as does wine, cider and beer. Peanut butter, avocado and raisins are other good sources of boron. You can also take boron as a supplement.

There is no recommended dietary allowance for boron to tell you how much you need each day. However there is a Tolerable Upper Intake Level (UL). UL is the maximum dose you can take, when you wouldn’t be likely to have any harmful effects. The National Academy of Sciences UL for boron is:

The National Academy of Sciences UL for boron is:
Children 1-3 years 3mg
Children 4-8 years 6mg
Children 9-13 years 11mg
Adolescents 14-18 years 17mg
Adults 20mg

Boron works with vitamin D to help your bones use the minerals they need, such as calcium. This ensures you have strong and healthy bones.


Don’t take boron supplements if you have kidney disease or your kidneys are not working well. This is because your kidneys need to work hard to get rid of boron from your body.

Vitamin A

Your body needs vitamin A for good eyesight, to help you fight infection and to keep your skin and mucous membranes healthy. Mucous membranes are the linings inside parts of your body such as your nose, your intestines and your lungs. Vitamin A is also important in the development of cells and is therefore vital for a baby developing inside the womb.

There are two main types of vitamin A:

  1. Beta-carotene, which you can get from brightly colored fruits and vegetables, such as carrots, apricots, mango and leafy greens.
  2. Retinol, which you can get from organ meats (such as liver) and dairy products such as butter, cheese and milk.

You can also take vitamin A as a supplement, both in the forms beta-carotene and retinol. However, it’s possible to take too much retinol, and as your body can’t get rid of it easily, this can be harmful. Your body can get rid of excess beta-carotene, however.

Don’t take more than the recommended daily allowance of vitamin A in the form of retinol. Vitamin A can also interact with a number of medicines, so if you’re thinking about taking a supplement and you’re taking medicines or have health problems speak to your physician for advice. If you don’t get enough vitamin D, you could be more at risk of the harmful effects of too much vitamin A.

Vitamin A and vitamin D work together to help your “genetic code” work properly. If you don’t have enough vitamin A, vitamin D may not be able to perform this function properly. On the other hand, research also shows that if you have too much vitamin A, vitamin D does not work as well. At this time, however, researchers don’t know how much vitamin D you need compared to how much vitamin A you need.

Our take

We think that humans most likely get enough vitamin A through diet and do not need to supplement with retinol.

Visit the Office of Dietary Supplements for more information on vitamin A


Too much vitamin A can be harmful to a developing baby, so if you’re pregnant don’t take vitamin A supplements. Don’t eat large amounts of liver or foods made from liver such as pate either, as these contain large amounts of vitamin A.