Have you noticed that colds seem to last longer than they used to? Perhaps cuts take longer to heal, or you find it harder to bounce back after an illness? 

These can all be signs that your immune system is changing with age. 

The good news is that while you can't stop your immune system ageing, there are plenty of ways to support it. These include healthy lifestyle habits, nutritional supplements and immune-support supplements such as AHCC® whose results look promising.

How does ageing and poor health affect the immune system?

The immune system is your body’s natural defence system. It works to protect you from viruses, bacteria and other harmful germs. Like the rest of your body, your immune system changes as you get older. 

Doctors call this immunosenescence, which simply means the gradual ageing of the immune system. These changes begin slowly in adulthood, but most people don’t notice much difference until their 60s. The effects become more noticeable in your 70s and beyond, although your lifestyle and overall health can affect how quickly your immune system ages. For this reason, it’s a good idea to start looking after your immune health in midlife, rather than waiting until problems develop.

Long-term health conditions such as diabetes, obesity and heart disease can also place extra strain on the immune system, making it harder to fight infections and recovery from illness slower.

Why does your immune system get weaker with age?

As you age, your body produces fewer new immune cells, and the cells you already have become less effective at recognising and fighting new infections. This means your body may take longer to respond to infections, making illnesses harder to fight off and recovery slower.

Many older adults also develop chronic low-level inflammation. Scientists sometimes call this inflammageing, a combination of the words inflammation and ageing. 

This is different from the inflammation which is part of the immune system and which helps your body to heal after an injury. It is a constant, low-grade inflammation that can gradually put extra strain on the immune system. It’s also been linked to health problems including heart disease, type 2 diabetes, and frailty. 

What are the signs of a weaker immune system?

It doesn’t always obvious symptoms, but you may notice that you:

• Catch infections more often
• Take longer to recover from coughs, colds or flu
• Heal more slowly after cuts or injuries
• Develop recurring chest or urinary infections
• Are more likely to get shingles.

If you find you are regularly getting ill, it’s important to speak to your GP.

Can you stop your immune system ageing?

Ageing is a natural process, so it’s impossible to stop your immune system getting older, just as you can’t stop getting older yourself. 

However you can help slow its decline and keep it working better for longer. Some of the most effective ways to support your immune system include:

• Staying mobile and active, including both aerobic exercise and strength training
• Eating a balanced diet rich in protein, fruit, vegetables, and whole grains
• Getting enough good-quality sleep
• Avoiding smoking
• Limiting alcohol
• Managing long-term health conditions
• Keeping your vaccinations up to date.

Healthy lifestyle habits will have the biggest impact. However, if your body is low on important nutrients, or if you are looking for additional immune support, some supplements have a role to play.

Should you take food supplements?

Eating a healthy, balanced diet is the best way to give your immune system the nutrients it needs. However, as we get older it can become harder to get enough of certain vitamins and minerals, either because our diet changes or because our bodies absorb them less effectively.

Some of the nutrients that are particularly important for a healthy immune system include vitamin D, vitamin B12, vitamin C, zinc, selenium, folate (vitamin B9) and protein. These nutrients help keep your body's natural barriers, such as your skin and the lining of your gut, healthy. They also help immune cells fight infections, regulate inflammation and protect cells from damage.

If you're deficient in one or more of these nutrients, taking a supplement may help restore healthy immune function. However, if you're already getting enough through your diet, there's little evidence that routinely taking extra vitamins or minerals will further strengthen your immune system. If you're concerned about your nutritional intake, it's worth speaking to your GP or another healthcare professional, who can advise whether supplements are appropriate.

AHCC®: a promising supplement

Alongside essential vitamins and minerals, some natural supplements are also being studied for their effects on the immune system. One of these is Active Hexose Correlated Compound (AHCC®), a natural extract made from the root-like part of the shiitake mushroom, called mycelia.

Unlike vitamins, which make up nutrients you may lack,  AHCC® is thought to work by helping the immune system work more effectively. Research suggests it supports important immune cells, including natural killer (NK) cells – one of the body's first lines of defence against viruses and other harmful germs. Because the activity of NK cells tends to decline as part of immunosenescence (the gradual ageing of the immune system), researchers are particularly interested in whether AHCC®  could help support the immune system of older adults. 

It may also help immune cells communicate with each other and support the activity of T cells, which play a key role in fighting infections.

Scientists describe this as an immunomodulatory effect, meaning it helps the immune system respond appropriately when its needed, rather than simply making it more active.

While these early findings are promising, more large, high-quality studies are needed before scientists can fully understand how effective AHCC® is, particularly in older adults.

Why should you start before old age?

You don’t need to wait until you are older to start thinking about your immune health.

While getting older inevitably changes the immune system, those changes don’t affect everyone in the same way. Looking after your health from midlife onwards though regular exercise, good nutrition, quality sleep and managing long-term conditions can can all help your immune system stay healthier for longer. It means quicker recovery after illness and staying independent in later life.

If needed, taking supplements to correct any you lack and potentially using well-researched supplements such as AHCC®, may provide extra support.