Are there diets or supplements that can improve the immune system of a male senior citizen?

1. Vitamin C
Infections can be prevented or their stay shortened with vitamin C. Citrus fruits are a standout, and there are other excellent sources to receive vitamin C from:
• Spinach
• Kale
• Bell peppers
• Brussels sprouts
• Strawberries
• Papaya
There is so much vitamin C in most foods that most people may not need to take supplements unless they have been advised to do so by their doctor. If you plan on taking vitamin C supplements, speak to your doctor first.

2. Vitamin E
The antioxidant properties of vitamin E help your body fight off infections, just as vitamin C does. As part of nearly 200 biochemical reactions in the body, vitamin C is essential for your immune system’s function. Vitamin E can be obtained from high-fat plant foods such as:
• Peanuts/peanut butter
• Sunflower seeds
• Almonds
• Oils such as sunflower, safflower, and soybean oil
• Hazelnuts

3. Vitamin A
A vitamin that fights infection, vitamin A can be obtained from animals like fish, meat, and dairy or from plants like carotenoids. Among the best sources for preformed vitamin A is tuna. To find the best carotenoids, eat colourful foods such as:
• Butternut squash
• Cantaloupe
• Dark green leafy vegetables
• Carrots
• Sweet potatoes
• Pumpkin

4. Vitamin D
Known as the sunshine vitamin, it is a nutrient that plays a pivotal role in maintaining a healthy immune system. The following foods are full of vitamin D:
• Tuna
• Sardines
• Salmon
• Mackerel
Vitamin D is fortified through milk, orange juice, and cereals. Generally, it’s best to get most of your vitamins from food, but vitamin D may be an exception. Talk to your doctor about whether you should take a supplement or not.

5. Folate/folic acid
A natural form of folate is folic acid, which is often added to foods for its health benefits. Regularly, include more beans, lentils, and leafy greens on your plate to obtain more folate. Avocado is also a great source of folate. You can also find folic acid in fortified foods (read the label first).
• Enriched pasta
• Enriched bread
• Enriched rice

6. Iron
• Your body uses iron to transport oxygen to cells, which helps maintain a healthy immune system. You can get iron in a variety of forms. Specifically, heme iron (aka iron from animal products) is easier for your body to absorb, as it is abundant in:
• Red meat
• Chicken
• Turkey
• Canned sardines
• Oysters
• Clams
• Mussels
• Canned light tuna
You need not be afraid if you are a vegetarian. It is still possible to get iron from:
• Beans
• Broccoli
• Kale
• Iron-fortified cereals

7. Selenium
The element selenium seems to have a powerful effect on the immune system, contributing to the prevention of infections. Except for Brazil nuts, which offer more than 100% of the daily recommended intake in one nut, animal foods provide the best sources of omega-3 fatty acids. But make sure you don’t take more than one or two of these each day. Selenium can be found in
• Seafood (tuna, halibut, sardines)
• Meat and liver
• Poultry
• Cottage cheese

8. Zinc
Zinc is required for the development of new immune cells. Most of its sources are animal foods, but some vegetarian foods contain them.
• Oysters
• Crab
• Lean meats and poultry
• Baked beans
• Yogurt
• Chickpeas