The digestive system needs stomach acid and a substance called intrinsic factor to absorb B12 effectively.

As people age, changes in stomach function can sometimes reduce B12 absorption.

Certain medications can also interfere with B12 absorption.

For example, long-term use of some acid-reducing medications and metformin has been associated with lower B12 levels in some people.

That doesn't mean people should stop prescribed medications.

Instead, if you're taking these medications long term, it may be worth discussing B12 status with your healthcare professional.

Vitamin B12 and Brain Health

B12 plays an important role in maintaining the nervous system.

Severe deficiency can cause neurological problems, including numbness, balance difficulties, and cognitive changes.

This is one reason unexplained neurological symptoms should be evaluated rather than dismissed as ordinary aging.

However, there is an important distinction:

Having adequate B12 is necessary for normal neurological function, but taking extra B12 when your levels are already adequate has not been established as a guaranteed way to improve memory or prevent dementia.

That distinction is often lost in online health content.

Correcting a deficiency is important.

Taking increasingly large doses when you aren't deficient isn't necessarily beneficial.

Where Can You Get Vitamin B12?

Good dietary sources include:

• Beef

• Chicken

• Fish

• Shellfish

• Eggs

• Milk

• Yogurt

• Cheese

• Fortified breakfast cereals

• Fortified plant-based foods

People following a strict vegan diet need to pay particular attention to B12 because reliable natural plant sources are limited.

A B12 supplement or fortified food may be necessary depending on the person's diet.

3. Vitamin C: Support for Immunity, Skin, and Connective Tissue

Vitamin C is probably one of the most familiar vitamins on this list.

People often associate it with oranges and immune health, but its functions are broader.

Vitamin C is an antioxidant and is necessary for collagen production.

Collagen is a major structural protein found in skin, blood vessels, bones, cartilage, tendons, and other connective tissues.

Vitamin C also helps the body absorb non-heme iron, the type of iron found primarily in plant foods.

Vitamin C and Immune Function

Vitamin C contributes to normal immune-system function.

That's why citrus fruits, peppers, berries, tomatoes, broccoli, and other vitamin-C-rich foods are useful components of a balanced diet.

But again, more isn't necessarily better.

Taking extremely high doses of vitamin C doesn't guarantee that you'll avoid colds or other infections.

In people who already get enough vitamin C, additional supplementation generally has limited benefits.

The goal is adequacy, not megadoses.

Vitamin C and Healthy Aging

Vitamin C becomes particularly interesting as we age because collagen production and tissue repair remain important throughout life.

Adequate vitamin C supports:

• Skin structure

• Wound healing

• Blood-vessel health

• Connective tissue

• Normal immune function

• Antioxidant protection

Severe vitamin C deficiency can cause serious problems, including fragile blood vessels, poor wound healing, and bleeding gums.

Fortunately, true deficiency is uncommon in people who regularly consume a varied diet.

Easy Ways to Get More Vitamin C

You don't necessarily need a supplement.

Try including foods such as:

Bell peppers

They can provide substantial vitamin C and are easy to add to salads, stir-fries, or sandwiches.

Citrus fruits

Oranges, grapefruit, lemons, and other citrus fruits are familiar sources.

Kiwi

Kiwi is particularly rich in vitamin C.

Strawberries

They provide vitamin C along with fiber and other plant compounds.

Broccoli

A useful source of vitamin C as well as several other nutrients.

Tomatoes

Fresh tomatoes and tomato-based foods can contribute vitamin C to the diet.