March 24, 2020

In response to the growing numbers of positive cases for the Coronavirus, many individuals are looking for ways to boost their immune system in order to fight COVID-19. I think even the greatest skeptics are starting to realize this is probably going to get worse before it gets better.

Notwithstanding Florida Springbreakers?

I’m sure your newsfeeds are flooded with information on ways to Boost Your Immunity with everything from Vitamins, Supplements, Essential Oils and of course the typical Magic Elixirs that promise immunity to all diseases.

There is a lot of misinformation out there and a lot of people looking to cash in by scamming the masses.

But the scams are not as unsettling as some of the things I’ve been hearing/reading the last few days regarding the actions people are taking to fight this virus.

I was at the pharmacy the other day and someone in line asked for Vitamin C. Apparently, Vitamin C and many other Vitamins and Supplements are out of stock until the foreseeable future.

It was the very next day I started to hear things like people taking double or triple doses of their multi-vitamin along with multiple servings of Vitamin C to “boost” their immunity.

While I applaud anyone trying to improve their health, “immune boosting” can have the opposite effect.

Megavitamin therapy involves consuming very large doses of certain vitamins in an attempt to prevent or treat diseases.

However, excessive amounts of different Vitamins can have very negative consequences.

First, please speak with your Doctor before taking any new Vitamins or Supplements, especially if you are on any medications. Vitamins and Supplements can react badly with other medications.

Second, before doubling or tripling any Vitamins or Supplements you are taking, please check the labels and make sure you aren’t already exceeding the RDA in any of these ingredients.

Some Vitamins are more of a risk for adverse side effects.

All Vitamins are classified into two groups: Water-soluble and Fat-soluble.

Water-Soluble Vitamins are easily dissolved in water and absorb into tissues for immediate use. They are not stored in the body and can be excreted in the urine. While this does NOT mean that you can take them in unlimited quantities, it does mean the risk of an overdose is very low.

Water-Soluble Vitamins are:

  • Vitamin B1 (thiamine),
  • Vitamin B2 (riboflavin),
  • Vitamin B3 (niacin),
  • Vitamin B6 (pyridoxine),
  • Vitamin B12 (cobalamin),
  • Folate,
  • Biotin,
  • Pantothenic Acid
  • Vitamin C

Vitamin C

Vitamin C in particular, is what everyone is taking more than normal. Vitamin C plays an important role in healing wounds, keeping your bones strong, enhancing brain function and believed by many to fight colds.

While it is unlikely you could die from taking too much Vitamin C, you might experience digestive distress.

The side effects of taking too much Vitamin C are typically cramps, diarrhea and nausea.

The RDA for Vitamin C ranges from 15–75 mg for children, 75 mg for adult women, 90 mg for adult men, and 85–120 mg for women who are pregnant or breastfeeding.

You will see that many supplements are above these limits.

If you are considering doubling your multivitamin and adding an additional Vitamin C supplement, do the math and I bet you might be way above the RDA.

Again, while Vitamin C has an overall low toxicity risk in healthy individuals, please stay well below the Upper Limits.

The UL (Upper Limit) established by the RDA is 400 for young children, 1,200 mg for kids aged 9–13, 1,800 mg for teens, and 2,000 mg for adults.

While there is relatively low risk with Water-Soluble Vitamins, Fat-Soluble Vitamins are a different story.

Fat-Soluble Vitamins are absorbed in fat. Excess fat-soluble vitamins are absorbed in the liver and fatty tissues. These Vitamins are not readily excreted and are therefore more likely to cause harm if taken over the RDA.

Fat-Soluble Vitamins are:

  • Vitamin A
  • Vitamin D
  • Vitamin E
  • Vitamin K

Vitamin A

The RDA for Vitamin A is 3,000 IU (900 mcg) for adult men and 2,333 (700 mcg) for women. For children, it ranges from 1,000 IU (300 mcg) to 2,000 IU (600 mcg). People are advised to avoid exceeding the upper limit for intake, which is 10,000 IU (900 mcg) per day for adults.

The most common side effects of chronic Vitamin A toxicity (often referred to hypervitaminosis A) includes vision disturbances, joint pain, bone pain, poor appetite, nausea and vomiting, sunlight sensitivity, hair loss, headache, dry skin, liver damage, jaundice, delayed growth, decreased appetite, confusion, and itchy skin.

Acute Vitamin A toxicity is less common than Chronic Vitamin A toxicity but has much more severe systems, including liver damage, increased cranial pressure and death.

Vitamin D

The RDA for vitamin D is 600 IU (15 mcg). The amount is slightly higher for elderly adults, at 800 IU (20 mcg). People are advised to avoid exceeding the upper limit intake, which is 4,000 IU (100 mcg), per day for adults.

Like Vitamin A, Vitamin D is very toxic in high doses. The most serious symptoms are caused by dangerously high levels of calcium in the blood, which can affect bones, tissues and other organs and lead to high blood pressure, bone loss and kidney damage.

Vitamin D toxicity can lead to Hypercalcemia (too much calcium in your blood) Symptoms include fatigue, loss of appetite, weight loss, excessive thirst, excessive urination, dehydration, constipation, irritability, nervousness, ringing in the ear (tinnitus), muscle weakness, nausea, vomiting, dizziness, confusion, disorientation, high blood pressure, and heart arrhythmias.

In severe cases, kidney stones, excess bone loss, abnormal heart rhythms, kidney failure and death can occur.

Again, if you are considering doubling your multivitamin and adding an additional Calcium supplement, do the math and I bet you might be way above the RDA. Vitamin D can be deadly, do NOT go above the UL.

Vitamin E

The RDA for Vitamin E is 23 IU (15 mg). For children and adolescents, the RDA ranges from 9 IU (6 mg) to 23 IU (15 mg), depending on the age group.

You are not as likely to overdose or experience negative consequences with Vitamin E as Vitamin A and D. However, there is a chance you could experience excessive bleeding, cause hemorrhages, and lead to hemorrhagic stroke. The Upper Limit is 1,500 IU (1,000 mg)

Vitamin K

The RDA for Vitamin K is 90 mcg for women and 120 mcg for men. The maximum safe dosage of vitamin K is unknown, and no symptoms of toxicity have been identified.

The Bottomline

If you are looking for ways to boost your Immune Systems by Megavitamin therapy, you might just do the exact opposite and crash your system, making you more susceptible to the Coronavirus.

Do your homework before taking multi doses of multivitamins or the additions of any new supplements, but most importantly, please chat with your Doctor, especially if you are on any medications.


Stay up-to-date on the latest recommendations for vitamins, minerals, herbs and botanicals, probiotics, and more with the websites listed below.


The IFPA Sports Nutrition Specialist and Advanced Sports Nutrition Specialist Certifications are designed for working fitness professionals to expand their scope of practice and add new revenue streams to their existing business by providing nutrition prescriptions for their clients through face-to-face training or online training sessions!

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