During my travels in Vietnam, one morning scene stayed with me.

Before sunrise on Nha Trang Beach, I often saw older adults walking, stretching, dancing, swimming, and talking with friends. Afterward, many would sit down to simple breakfasts built around vegetables, broth, herbs, fish, rice, and other familiar foods.

What interested me was not a miracle food or supplement.

It was the consistency of their habits.

That observation also connects with something I have learned during more than 40 years working in stainless-steel cookware development and manufacturing: good ingredients matter, but how we prepare them matters too.

Now that I am in my seventies myself, I think about food differently than I did when I was younger. I am less interested in complicated rules and more interested in practical habits that can be repeated every day.

Food cannot guarantee immunity or prevent illness. But a balanced diet can provide nutrients our bodies need for normal immune function.

And the kitchen is where many of those everyday choices begin.

Why Immune Function Changes With Age

Our immune system changes as we grow older.

Scientists often use the term immunosenescence to describe age-related changes in immune function. Aging can affect how effectively the body responds to infections and other challenges.

This does not mean that getting older automatically means becoming unhealthy.

It does mean that nutrition, physical activity, sleep, appropriate medical care, vaccination, and other healthy habits become increasingly important.

For me, food is one of the most practical places to start.

Rather than looking for one “immune-boosting” ingredient, I prefer to think about a varied eating pattern that regularly provides protein, vegetables, fruits, whole grains, healthy fats, and important micronutrients.

1. Vitamin C: Fresh Foods and Gentle Preparations

Vitamin C contributes to normal immune function and acts as an antioxidant.

Good food sources include:

• Bell peppers
• Broccoli
• Kiwi
• Citrus fruits
• Strawberries
• Tomatoes
• Leafy vegetables

There is an important cooking lesson here.

Vitamin C is water-soluble and sensitive to heat. Cooking vegetables in large quantities of water and then discarding that water can result in the loss of some water-soluble nutrients.

That doesn’t mean vegetables should always be eaten raw.

Instead, I often use a simple principle:

Use only as much heat, water, and cooking time as the food needs.

For vegetables such as broccoli or bell peppers, I prefer brief cooking with minimal added water when appropriate, stopping while the vegetables still have good color and texture.

This is one reason my cooking philosophy has long emphasized using the ingredients’ own natural moisture whenever possible rather than automatically boiling them in a pot full of water.

2. Zinc: An Important Nutrient for Normal Immune Function

Zinc is another nutrient involved in normal immune function, wound healing, and many cellular processes.

Food sources include meat, seafood, beans, lentils, seeds, nuts, dairy products, and whole grains.

Oysters are particularly rich in zinc, but they certainly aren’t the only option.

For people who rely primarily on plant foods, beans, lentils, pumpkin seeds, and whole grains can contribute zinc to the diet.

Plant foods also contain compounds called phytates, which can reduce mineral absorption. Traditional preparation methods such as soaking beans and lentils before cooking may help reduce some phytate.

There is no need to turn this into a complicated nutritional calculation.

I prefer variety: different whole foods throughout the week rather than depending heavily on one ingredient.

Anyone considering zinc supplements—especially in larger doses or for long periods—should discuss them with a healthcare professional.

3. Vitamin D Deserves Attention After 60

Vitamin D has several roles in the body, including supporting normal immune function and bone health.

Food sources are more limited than they are for many other nutrients. They include fatty fish such as salmon, sardines and mackerel, egg yolks, certain UV-exposed mushrooms, and foods fortified with vitamin D.

Our bodies can also produce vitamin D when skin is exposed to sunlight, although many factors affect how much is produced.

For older adults, vitamin D status can be worth discussing with a doctor because individual needs vary and a blood test may sometimes be appropriate.

From a cooking perspective, I keep things simple.

I prefer to cook fish only until it is safely done rather than subjecting it unnecessarily to prolonged, aggressive heat. The result is usually better texture and flavor as well.

4. Colorful Vegetables: Variety Matters More Than a “ Superfood “

When people ask me which vegetable is healthiest, my answer is usually:

Don’t look for one. Eat different colors.

Dark leafy greens, broccoli and other cruciferous vegetables, tomatoes, carrots, sweet potatoes, peppers, berries and many other plant foods provide different vitamins, minerals and naturally occurring plant compounds.

There is also an interesting lesson about cooking.

Raw is not always nutritionally superior.

For example, cooking tomatoes can increase the availability of lycopene, while cooking carrots can improve the accessibility of some carotenoids.

So my approach is not:

“Raw is good and cooked is bad.”

It is:

Choose the cooking method that suits the ingredient.

Some foods are wonderful raw. Others benefit from light cooking. Some need thorough cooking for safety or digestibility.

After decades around cookware, I have learned that good cooking is often about balance rather than extremes.

5. Fermented Foods and the Gut

The relationship between the gut microbiome and the immune system is an active and fascinating area of research.

Fermented foods can be part of a varied diet. Depending on how they are produced and processed, foods such as yogurt, kefir, kimchi, sauerkraut and some fermented vegetables may contain live microorganisms.

But there is an important distinction:

Not every fermented food contains live cultures by the time we eat it.

Pasteurization and heating can reduce or eliminate live microorganisms.

For foods purchased specifically for live cultures, check the label.

At home, I often enjoy fermented foods as part of the meal rather than treating them as medicine. Kimchi can accompany rice and vegetables; plain yogurt can be eaten with fruit; miso can add flavor to a soup.

The point is not to consume huge quantities.

It is simply another way to bring variety to the table.

The Cooking Principle I Have Followed for Decades

After more than 40 years working with stainless-steel cookware, I keep returning to a few simple ideas:

Use fresh ingredients when possible.

Avoid unnecessary water.

Avoid unnecessary cooking time.

Use enough heat to cook food properly and safely, but don’t assume that more heat is always better.

This philosophy eventually became very simple for me:

No Water When It Isn’t Needed. No Added Sugar When It Isn’t Needed.

Vegetables already contain water. Tomatoes contain water. Mushrooms contain a remarkable amount of water. Meat and fish also release moisture during cooking.

A tightly covered pan can often use some of that natural moisture.

That does not mean every food should be cooked without water. Soup, rice, pasta, dried beans and many other dishes obviously require liquid.

The idea is simply to stop adding water automatically when the ingredient does not need it.

That is a cooking principle—not a medical claim—and it has shaped the way I prepare food today.

A Simple Week of Foods That Support Good Nutrition After 60

Rather than following a complicated “immune diet,” I would build meals around variety.

During a typical week, that might mean broccoli or peppers cooked briefly; tomatoes and carrots served raw or cooked in different dishes; beans, lentils, nuts or seeds; eggs and fish; fresh fruit; leafy vegetables; whole grains; and small servings of fermented foods if you enjoy them.

Most importantly, I would vary the ingredients.

A colorful, balanced plate repeated consistently is more realistic than chasing the latest superfood.

What I Have Learned in My Seventies

Travel has taught me as much about eating as any kitchen.

In Vietnam, I watched older people gather at the beach before sunrise to exercise together.

In Korea, I have seen meals built around vegetables, soups, fish, grains and fermented side dishes.

Different countries have different traditions, and no single food culture has all the answers.

But I keep noticing the same valuable idea:

healthy eating is usually a pattern, not a product.

It is the vegetables you eat repeatedly.

The fish, beans, eggs and other protein foods you rotate through the week.

The amount of heavily processed food you replace with simpler ingredients.

And, importantly for someone who has spent most of his professional life around cookware, it is also learning when food needs high heat, when it needs gentle heat, when it needs water—and when it doesn’t.

I don’t believe a single food, pot, supplement or cooking method can “boost” the immune system.

But I do believe that preparing good food thoughtfully is one practical way we can take better care of ourselves as we grow older.

That is the kind of healthy cooking I want to continue exploring at my own table.

Join Me at Grandpa Pot’s Healthy Table

I spent more than four decades developing and manufacturing stainless-steel cookware. Today, in my seventies, I am revisiting what those years taught me while traveling, cooking, and learning from the food traditions I encounter.

On Grandpa Pot’s Healthy Table, I share practical cooking ideas, travel observations, and lessons about preparing simple food with less unnecessary water, sugar and excessive cooking.

You can also find my videos and other stories through my Linktree, where I keep my latest content together:

Linktree: linktr.ee/peterpark3126

If you are also trying to eat more simply and thoughtfully as you get older, I hope you’ll join me. We can keep learning together—one meal at a time.

This article is for general educational purposes and is not medical advice. Nutritional needs, medical conditions and medications vary by individual. Older adults considering major dietary changes or supplements should discuss them with a qualified healthcare professional.