How Does the Immune System Change With Age?


Our body changes as we age. It’s a natural part of existing just like the sun rising and setting each day. Our immune system is, well not immune, to the passing of time. And as we get older, it also experiences some changes.

It’s important to understand how it changes and what you can do to support it each step of the way.

What Is The Immune System?

First, let’s get an understanding of what the immune system is. It is a network of cells, tissues and organs that all work together to defend the body from parasites, bacteria and other substances that can cause illnesses and infections (1).

Cells that are a part of this defense system are called white blood cells or leukocytes, while the invaders are known as antigens.

Everybody’s immune system is different. As we get older, we’ve developed immunity to some of these invaders, which is why adults sometimes don’t get sick as often as children do. However, as we age, the immune system also loses some of its defense including:

  • The thymus shrinks. This organ is part of the immune system and starts to get smaller when we are young adults.
  • T cell function decreases. These help work to kill antigens.
  • Macrophages don’t work as fast either. These white blood cells ingest antigens.
  • The amount of antibodies produced in response to an antigen decreases as we get older.
  • The body sometimes becomes less tolerant of its own cells sometimes developing into an autoimmune disorder like lupus and rheumatoid arthritis.
  • Diabetes decreases immunity.

How To Increase Immunity In Adults

Fortunately, there are some ways to have the strongest immune system possible. The first and possibly most important thing you can do is lead a healthy lifestyle (2). Some people underestimate how important making healthy choices can have not just on the immune system, but the whole body. Start by following these strategies.

  • Eat a diet full of fruits and vegetables
  • Make exercise a priority
  • Maintain a healthy weight
  • Don’t smoke
  • Drink only in moderation
  • Get enough sleep every night
  • Minimize stress
  • Wash your hands regularly

In addition, it’s important to properly prepare foods such as meats to make sure they are cooked thoroughly to avoid any illnesses.

It’s also especially important to make sure you are eating a variety of healthy foods like fruits and vegetables. Older adults are more susceptible to something called “micronutrient malnutrition.” This happens when people are deficient in some trace vitamins and minerals. It often happens in older adults because they sometimes eat the same foods lacking the variety needed to ensure adequate consumption of different kinds of nutrients.

When Does Your Immune System Peak?

Our immune system is still developing after we are born and continues to get stronger as we age, but at what age is the immune system fully developed? It generally peaks around puberty and gradually starts to decline after that. 

Puberty generally begins between 8 and 14 years of age. Girls can start younger at age 8 and boys tend to start a little older around 9. But it can start anytime between those ages. 

At What Age Does The Immune System Decline?

The immune system changes dramatically when people are in their 60s. This aging immune system loses its ability to protect against infections as well as cancer. Wounds may also take more time to heal. Older adults often have impaired responses to vaccines. Aging is also linked to an increased incidence of inflammatory disease.

Our survival is linked to having a healthy and functional immune system. It has fast and effective responses, but lacks long-term memory. The immune system functions by recognizing an antigen, memory formation and proliferation of the cells that provide antigen-specific immunity.

How Can Seniors Improve Their Immune System?

As we get older, we experience immunosenescence, especially the elderly. This is basically the changes that happen in our immune system as we age. But fortunately there are some things we and especially seniors, can do to improve our immune system. It all starts with what we eat.

Fruits And Vegetables

It’s important to eat the rainbow, which just means eat a variety of fruits and vegetables. Blueberries, broccoli, kale and avocados receive the gold star due to their high levels of vitamin C, antioxidants and anti-inflammatories. Don’t forget to also add these:

  • Bell peppers
  • Berries
  • Citrus
  • Apples
  • Leafy lettuce including spinach
  • Almonds

Lean Protein

The body needs protein, but make sure it is lean cuts like turkey and skinless chicken. Lean cuts of beef are okay too. Soy also works, especially if you don’t eat meat. And don’t forget fish. It is high in omega-3 fatty acids which is good for brain and heart health as well. 

Whole Grains

Besides providing fiber, whole grains provide needed vitamins B and E. So make sure to add:

  • Oatmeal
  • Whole grain breads and pasta
  • Whole grain cereal
  • Quinoa
  • Barley

Herbs And Spices

These do more than just provide some extra flavor to each meal. They are full of their own health benefits. Try adding these powerhouses:

  • Turmeric and ginger - Help repair damaged cells
  • Oregano - Helps support body’s own natural resistance
  • Cinnamon - High in antioxidants 
  • Echinacea - Has antiviral properties 
  • Ginseng - Helps brain function


Staying hydrated is important to keep the mucus membranes moist, which helps avoid colds and the flu. Water is the recommended beverage of choice, but tea and even broth count.


Getting needed nutrients from food is recommended, but not always possible so you may need to add vitamins. This ensures you fill in any nutritional gaps.

At What Age Is the Immune System Fully Developed?

The immune system is ever evolving from the time we are born and even past development as we get older due to any antigens we encounter during our lives. However, the immune system is fully developed around 7-8 years of age. 

Supplements Can Help Support Your Immune System

As part of a healthy lifestyle, supplements may be able to help support the immune system. Please note, we cannot claim to cure or heal any diseases or illnesses.

Spermidine is a supplement found in food that can help trigger the body’s autophagy process. This process plays a huge role in building a strong immune system by helping the body get rid of dysfunctional cell components in order for new and healthier ones to be formed. 

Spermidine may also help support cellular immunological memory, which is when our cells recognize an antigen to fight it off. So spermidine may help boost the body’s defenses.

Spermidine doesn’t just provide support for the immune system, it supports the body as a whole since our body is made up of cells. When cells function at the highest level possible, we have the best chance of living a long and healthy life.


  1. Aging Lowers Your Immunity
  2. How to Boost Your Immune System
  • Don Moxley - Director of Applied Science

    Don Moxley is the Director of Applied Science at Longevity Labs. Moxley draws upon his career as an athlete, a sports scientist, and an instructor to lead and educate on the science of autophagy and longevity.