Your guide to a resilient immune system in later life

Your immune system is made up of two parts. The innate and the adaptive immune systems. The innate immune system can be called the first responders, and the adaptive immune system is the highly trained special forces.

The innate immune system responds to infective threats. 

It’s like security guards that are always on duty. It responds very quickly (within hours) to any threat. If bacteria have entered through a small wound on your skin, the innate immune system responds immediately and destroys the infection. They also have chemical defences in sweat, tears, and mucus membranes. They have special cells that immediately attack anything that looks foreign. But it can’t always stop the germs from spreading.

That job is left to the adaptive immune system.

The adaptive immune system is specialized in that it targets the type of germ that is causing the infection. To do that, it has to recognize the germ. Once it does that, it is able to “remember” that germ and can mount an immediate response to eliminate that germ if encountered again. Unfortunately, that means that the initial process of identifying the germ takes time. It can take 4–7 days for the adaptive immune system to learn about the germ, inform the other parts of it, and mount a response by producing very specific antibodies tailor-made to fight the specific infection.

Both parts of the immune system are important.

The innate immune system (the first responders) controls the infection until the adaptive immune system (specialist forces) can ramp up to create specific antibodies to eliminate the infection. Sometimes a severe infection can overwhelm the immune system and be life-threatening. Those are the times when antibiotics may have to be used and they become lifesavers.

All throughout life we are constantly facing potential infections.

We inhale bacteria or viruses from someone with a cold, but we don’t necessarily get the infection. We get a scratch, but it heals over without developing an infection. Our immune systems are doing their job 24/7. 

Sometimes minor infections can overwhelm the older person’s immunity. 

They can take a long time to recover. There are 2 reasons for that. One is that the adaptive immune system naturally declines with age, making it more challenging to fight infections. The other reason is that paradoxically, the innate immune cells increase in numbers with age.

For that to make sense, we need to understand the way the innate immune system works.

One way it fights infection is to produce inflammatory chemicals that kill the germs. Once the infection is under control, the cells switch to releasing anti-inflammatory chemicals to stop the inflammation. With ageing, the other system, the adaptive immune system, slowly fails to recognize intruders, so the innate immune system ramps up to cope, releasing more inflammatory chemicals. This is especially so because, as explained, we are constantly facing minor bacterial or viral infections. With the constant release of inflammatory chemicals by the innate immune system, the body gets to a chronic state of low-grade inflammation. This is often referred to as "inflammageing.”.

This chronic low-grade inflammation can lead to other conditions.

Impaired immune function can lead to increased susceptibility to infections, poorer vaccine response, and a higher incidence of age-related diseases such as Alzheimer's disease, osteoporosis, and diabetes. These connections will be covered in other newsletters.

Now, for the most important part. 

There is a lot we can do to improve the immune system as we age. The earlier we start, the better. Obviously, it will be harder to improve an immune system that is already compromised than to maintain an already healthy system. So the degree of improvement will vary depending on where you are, but one should be able to expect some improvement in most cases. 

First is exercise.

You will find that as we go through the various aspects of ageing, exercise will feature in most of them. The research is compelling for maintaining or even improving overall health for healthy ageing. 

Engaging in long-term physical activity can enhance immune function and reduce the risk of infections. Exercise also helps maintain muscle mass and strength, which are crucial for a healthy immune system. In addition, I mentioned above how, with ageing, the innate immune system produces more inflammatory chemicals, leading to chronic inflammation. Exercise can help switch the process to produce anti-inflammatory chemicals. We will be covering the value of exercise in Healthy Ageing in other newsletters.

A word of caution: Depending on your age and level of fitness, it is important that you talk to your doctor before engageing in a new or different exercise program. 

Diet

A balanced diet rich in fruit, vegetables, whole grains, and proteins is essential for a healthy immune system.

The Mediterranean diet has been shown to improve various immune parameters in elderly individuals. I am not a proponent of “one diet for everyone,” but the Mediterranean diet is a proven one if you do not have food allergies. We will be talking a lot more about diet generally and the different types in other newsletters.

Specific Supplements

• Multivitamins and minerals: Supplementation in an elderly population improves vitamin C and zinc status, both of which are crucial for immune function.

• Vitamin E has been shown to improve immune responses in the elderly.

• Zinc supplementation can rectify deficiencies common in the elderly. Zinc is an important mineral for immune function. Supplementation should be considered if blood levels of zinc are low, as high zinc levels can lead to other problems.

• Probiotics. Specific probiotics like Bifidobacterium longum, Lactobacillus helveticus, and Bifidobactrium lactis have been shown to enhance immune responses.

The immune system is not just about infection control. It is important for the prevention of cancer, autoimmune disease, and other chronic illnesses. We will be covering each of these in detail in other newsletters.

For healthy ageing, we need a robust immune system, and the 2 crucial actions are regular exercise and a balanced diet. These 2 simple actions can help ensure your first responders and the specialist responders of your immune system don’t work against you. 

References:

1. A brief outline of the immune system PMID 25048116

2. Age-dependent dysregulation of innate immunity PMID: 24157572 

3. Physical activity and diet shape the immune system during ageing. PMID 32121049

4. The effect of a multivitamin and mineral supplement on immune function in healthy older adults: A double-blind, randomized controlled trial PMID 32823974

5. Vitamin E supplementation enhances cell-mediated immunity in healthy elderly subjects PMID 2203257

6. Supplementation with B. longum and L. helveticus mixture improves immunity in elderly humans (over 75 years) and aged mice. PMID 31029046

Medical Disclaimer:

This newsletter is for general informational purposes only and does not constitute medical advice. The content should not replace professional medical advice, diagnosis, or treatment. Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read in this newsletter. Reliance on any information provided here is solely at your own risk.