At a time when most people want their immune systems to be functioning optimally, research indicates that many Americans are not getting adequate levels of immunity-boosting nutrients (Nutrients, June 10, 2020).
Which Immunity-Boosting Nutrients Are Low?
The investigators used data from the 2005-2016 National Health and Nutrition Examination Surveys. People surveyed were consuming inadequate levels of four out of five nutrients considered key for immune health.
For example, 45% of US adults were not getting adequate vitamin A and 46% were not getting adequate vitamin C. Even fewer had diets supplying adequate vitamin D. Approximately 95% did not meet guidelines. In addition, the researchers found that 84% of adults got too little vitamin E. Moreover, 15% were low in zinc intake.
What Foods Provide These Immunity-Boosting Nutrients?
How much vitamin A you need depends on age, gender and life stage. You can consume a lot of vitamin A if you eat liver–but most people don’t. Green leafy vegetables provide carotenoids, precursors to vitamin A. Think about spinach, broccoli and kale. Don’t forget colorful veggies: sweet potatoes, carrots, squash and peppers, green and red. Orange and yellow fruit such as mangos, cantaloupe and apricots are great sources, too. Fish such as herring, salmon and tuna offer vitamin A. So do fortified dairy products.
The Institute of Medicine recommends 90 mg of vitamin C daily for men and 75 mg daily for women. Smokers and those who live with smokers need more of this vitamin. Where do you find it? Red peppers have plenty in half a cup. Citrus fruits like oranges and grapefruit also provide this immunity-boosting nutrient. Don’t overlook kiwifruit, strawberries and tomatoes. In addition, broccoli, Brussels sprouts, cabbage and cauliflower offer good amounts of vitamin C.
It could be a challenge for most adults to get the RDA of 15 to 20 mcg a day from food. You could do that with a serving of rainbow trout or sockeye salmon. But it would take almost a cup (more than a single serving) to get 15 mcg from mushrooms. The best source is cod liver oil, with 34 mcg per tablespoon. No wonder so few Americans have adequate dietary intakes of vitamin D!
American adults should get about 15 mg of vitamin E daily. You could manage that with one tablespoon of wheat germ oil, but we are guessing that’s not much more popular than vitamin D-rich cod liver oil. Other sources of vitamin E include sunflower seeds, almonds and hazelnuts. Sunflower and safflower oil each provide about 1/3 of a day’s requirement per tablespoon. Peanuts and peanut butter have some. If you eat spinach or broccoli for their vitamin A or C content, you’ll also get some vitamin E.
The stars when it comes to zinc are oysters. Not on your daily menu? We didn’t think so. Luckily, beef, pork and seafood (crab, lobster) are also strong sources of this immunity-boosting nutrient. Where does that leave vegetarians? One serving of baked beans or fortified breakfast cereal could provide about a quarter of the day’s RDA (11 mg for adult men, 8 mg for women). Pumpkin seeds, cashews, chickpeas and almonds can also contribute to your zinc intake.
People who took vitamin pills were less likely to fall short than those relying on food alone.
The authors conclude:
“—public health measures should adopt guidelines to ensure an adequate intake of these micronutrients, especially in vulnerable populations.”