The key to ironclad immunity lies with these five basic nutrients

Have you ever noticed that some people tend to get sick all the time? Whereas other folks rarely even get the sniffles. And if they do catch a virus, they get over it quickly.

Well, the difference between these two types of people isn’t just luck of the draw. Quite the contrary, actually.

The truth of the matter is, folks who rarely get sick have a healthy immune system that quickly sweeps into action when needed—to defend against all the viruses, bacteria, and microbes circulating, especially at this time of year.

So, today, let’s talk about how you too can build a strong immune system—starting with five basic nutrients that should already sound familiar to you…

Five bulletproof ways to help keep viruses at bay

1.) Vitamin A

Studies show vitamin A plays a critical role in maintaining a healthy immune system. In fact, research links adequate vitamin A with a much lower risk of catching nasty respiratory and gastrointestinal (GI) infections.

But there’s a catch…

As I explained last fall, mainstream medicine worries about the supposed dangers of getting “too much” vitamin A. The concern dates back more than a century to a group of artic explorers who got very sick by eating polar bear livers, which are high in the vitamin.

Of course, I don’t imagine that you’ll be eating polar bear livers any time soon. But I do advise against taking vitamin A supplements in the form of retinol, as they can also pose potential problems. This type of vitamin A is fat-soluble, which means your body absorbs it and stores it in the liver and other tissues. So, it can potentially build up, if taken in high enough doses.

Fortunately, there’s a healthy work-around…

Simply eat plenty of yellow, orange, and red fruits and vegetables, which contain high amounts of carotenoids. Your body safely converts the carotenoids into vitamin A. Plus, unlike retinol, carotenoids are water-soluble and do NOT build up in your tissues. So there’s never a risk of “overdose.”

2.) B vitamins
As I’ve explained before, there are eight B vitamins, and they’re all essential for building up your defenses against viruses and infections.

Specifically, we know B6 helps the body make red blood cells and immune system cells. And a deficiency in B6 depresses immunity.

Likewise, lack of folate and B12 can result in reduced blood cell counts—including fewer white blood cells, which the body needs to fight infections.

Other B vitamins—including pantothenic acid, riboflavin, and thiamin—also play important roles in supporting a healthy immune response.

Of course, unlike vitamin A, B vitamins are water-soluble, meaning you can’t store them in fat cells or tissues. So, it’s important to get a regular supply from the foods you eat. You can find B vitamins in free-range, organic meat, full-fat dairy, eggs, green leafy vegetables, beans, seafood, and whole grains.

However, studies show that many people don’t get enough B vitamins from their diet alone. So, I recommend taking a high-quality vitamin B complex supplement that contains at least 55 mg of B6.

3.) Vitamin C
We’ve known for decades that vitamin C is a powerful immune-booster that helps encourage the production of white blood cells. In fact, studies show that supplementing with this basic nutrient not only helps shorten the duration of the common cold, but it also lessens its severity.

But really, you should take vitamin C year-round, not just when you’re feeling sick. For one, it’s another a water-soluble vitamin, meaning it won’t “build up” in your tissues. Second, it’s critical for the growth and repair of all the tissues and cells in your body. Third, as a strong antioxidant, it protects cells from harmful free radicals that lead to chronic disease, including cancer.

So, I recommend you take 250 mg of vitamin C twice a day, year-round.

4.) Vitamin D

As you know, there are various misconceptions about vitamin D circulating the mainstream. (You can read all about them in the September 2019 issue of my monthly newsletter, Insiders’ Cures [“Debunking the latest ‘fake news’ about vitamin D”].) But let’s recap what we know…

A wealth of studies show that vitamin D is critically important to human health. For one, we now know it goes to work right inside your gastrointestinal (GI) microbiome, the environment in your gut where billions of healthy bacteria thrive, before ever reaching your tissues. So, it protects you against just about every chronic disease on the planet!

It also plays a critical role in keeping your immune system healthy and balanced. Which means it can help you quickly mount an attack against invaders, should you become exposed to a virus or the flu.

Not to mention, research shows that patients with adequate blood levels of vitamin D experience fewer and milder colds and cases of the flu if the first place!

(Remember, you’ll want to achieve blood levels of 50 to 75 ng/mL. Ask your doctor for a simple blood test called the 25(OH)D to check your levels twice a year—once towards the end of winter, and again towards the end of summer.)

So, if you haven’t already started taking vitamin D, now’s the time. I recommend supplementing year-round with 10,000 IU of vitamin D3 daily. (You can now find this dose in a convenient, highly-absorbable liquid form together with the potent marine carotenoid astaxanthin for added benefits. For more information, simply type “astaxanthin” into the top right search bar of my website.)

And come April, when the sun starts to get higher in the sky, aim to spend 15 minutes a day in the sun without sunscreen to activate your skin’s natural production of vitamin D.

5.) Vitamin E

You may remember about 15 years ago, vitamin E got a bad rap in the mainstream press because a very poorly designed meta-analysis found that men and women who took 400 IU or more each day had a higher overall mortality risk. But the study was a complete mess with very unreliable results. Of course, that’s the only thing about E that many doctors know and remember.

Since then, many strong studies have come out to show that vitamin E is not only safe, but also enhances immune response by boosting white blood cell activity. Especially among older adults.

In fact, one recent study found that 200 IU per day of vitamin E was effective in protecting residents in a long-term care facility from coming down with the common cold.

The government currently recommends 15 mg of vitamin E per day for adults. But broad surveys show that 90 percent of men and 96 percent of women don’t even consume that minimal amount. Not to mention, research indicates that the optimal daily intake should be much higher.

So, considering this wealth of research, I recommend supplementing with 50 mg of vitamin E per day. But more importantly, you should also incorporate more vitamin E-rich foods into your diet. Some of the best sources are nuts, seeds, spinach, eggs, and fish. (Note that the vitamin E in eggs is found in the yolk. So be sure to eat the whole egg—not just the white.) Eating more of these foods is vital for your general health in any case.

There you have it! At the end of the day, your takeaway is this…

The key to becoming a “never-get-sick” kind of person is to build a strong, balanced immune system, which you can achieve by maintaining a healthy, balanced diet along with key supplementation all year long.

Tune back in for Thursday’s Daily Dispatch about key minerals—and even some specific foods—that can help you fight off winter’s worst, too.


“Increased risk of respiratory disease and diarrhea in children with preexisting mild vitamin A deficiency.” Am J Clin Nutr. 1984 Nov;40(5):1090-5.

“Vitamins: Key Role Players in Boosting Up Immune Response-A Mini Review.” Open Access Journals, 3/7/2017. (

“Foods, fortificants, and supplements: Where do Americans get their nutrients?”  J Nutr. 2011;141:1847-54.