Our immune system plays a vital role in our health as it protects us from infection and disease. The immune system consists of specialized cells, proteins, tissues and organs and protects us every day from invading microorganisms and viruses. Various factors can affect or weaken your immune system, including stress, lack of sleep, poor diet, sedentary lifestyle, and poor hand hygiene. One question that doctors and scientists have been investigating is whether the immune system gets weaker with age. We have compiled the information from several studies and scientific articles in which researchers examined the effects of aging on our immune systems. Read on to find out how the immune system changes with age.
How does the immune system change with age?
Dr. Peter J. Delves, Professor at University College London, offers an overview of the effects of aging on the immune system in an article on the online portal merckmanuals.com.
This is why the immune system declines with age:
- With age, the immune system is less able to remove healthy cells and tissues from foreign ones Differentiate antigens. As a result, autoimmune diseases such as rheumatoid arthritis and lupus are more common.
- Macrophages, which belong to the so-called phagocytes no longer act as quickly as they used to against bacteria, cancer cells and other antigens. This slowdown could be a reason cancer is more common in the elderly.
- Of the Thymus, located behind the breastbone, is an important organ of the lymphatic system and one of the most important parts of the immune system. In the thymus, the T cells mature from stem cells. After puberty, however, the thymus begins to degenerate until it has lost around 85 percent of its size in adulthood.
- T cells respond not so quickly on antigens, i.e. unwanted intruders, even those they have met. Although the number of T-cells does not decrease with age, the T-cell function for immune defense decreases.
- There is fewer white blood cells, that are able to respond to new antigens. So when older people encounter a new antigen, the body cannot remember it and fight back against it.
- Older people produce smaller amounts of Complement proteins, which serve to defend against microorganisms (e.g. bacteria, fungi, parasites) in response to bacterial infections.
- Although the amount of antibodies produced in response to an antigen remains about the same, the antibodies can no longer adhere so well to the antigen. This change could be partly a reason why conditions like flu, pneumonia, and tetanus are more common in the elderly and also lead to death. It also explains why vaccines are less effective in older people and why it is therefore important that older people receive booster vaccinations.
A study by Austrian scientists showed that, for example, the effectiveness of the tetanus vaccination decreases from the age of 40. At the age of 60, 16 percent of those vaccinated in the past five years were no longer fully protected. And conventional flu vaccines are only 30 to 40 percent effective in people aged 65 and over.
These changes in immune function can make the elderly more susceptible to certain infections and cancers. Now we want to provide more information on some of these immune system changes with age. And in this article we have summarized the most important tips on how people aged 60 and over can strengthen their immune system.
Immune system in old age: T lymphocytes and the regression of the thymus
A report entitled “T cell aging: Effects of age on development, survival & function ”, which was published in the journal“ Indian Council of Medical Research ”in 2013, describes the age-related decline in the immune system as a major health problem. The publication states that “the role of T cells during aging is increasingly becoming the focus because of their effects on general immune responses.” Here are the key facts from the study.
The deterioration in the immune system in the elderly is often referred to as “immune senescence”. A major factor in immunosenescence is the process of thymic involution, a gradual regression of the thymus with age. The thymus is the main immune system gland and lies behind the breastbone.
The main components of adaptive immunity are T and B lymphocytes. T-lymphocyte precursors migrate from the bone marrow and colonize the thymus. All important events such as the development of functional lymphocytes and tolerance to self-antigens take place in the bone marrow for B cells and in the thymus for T cells. After they mature, these lymphocytes enter the bloodstream and develop suitable immune responses against foreign antigens.
But after sexual maturity this organ begins to regress. By the age of 40 he has lost 80 percent of his size, making him less effective at converting white blood cells into fully functional T cells. This regression of the thymus leads to a steady decline in the production of naive T cells, which leads to a restricted immune repertoire for the detection of pathogens.
The thymus gland also becomes cluttered with fat cells as it ages. By the age of 45, long before most other organs show any signs of aging, nearly 80% of the thymus has been converted to fat. While it’s not clear where these fat cells came from or why they’re there in the first place, the damage they do is devastating. This explains why the elderly have weaker immune systems. However, it is still not entirely clear why the thymus gland ceases to function.
Yale Scientific published an article in 2016 about a study by Vishwa Deep Dixit, professor of immunobiology at the Yale School of Medicine. He discovered a hormone that can help reactivate the thymus after it has regressed. This hormone, known as fibroblast growth factor 21 (FGF21), can stimulate thymus function and prevent our immune systems from weakening as we age. This finding may offer promising treatment for strengthening immunity in the elderly and in cancer patients who have had bone marrow transplants. More research is needed before this hormone can be given as a drug to improve thymus function. Dixit and his team are working to turn this into an effective therapy. If successful, a tiny hormone could save the aging immune system.
A healthy bowel is the key to our wellbeing
Scientists at the Norwich BioScience Institute have carried out the first detailed study of how our intestinal tract changes with age and how this affects our general health. This information is important because “the gut plays a central role in programming our immune system and is an effective barrier against bacteria that could make us sick. Immune cells that colonize the intestine are particularly important for the defense against bacterial pathogens.
Here are the key facts from the study:
- Changes in the structure and function of the intestinal barrier contribute to the fact that our immune system weakens with age and the risk of infections and diseases increases.
- The researchers found that with age, the intestines show an increase in a specific regulator of the immune system called interleukin 6 (IL-6), which causes inflammation.
- Inflammation is increasingly seen as an important factor in the aging process. The study results suggest that the intestine plays a crucial role in inflammatory processes.
- It’s important for scientists to develop methods of controlling inflammation to prevent colon cancer, inflammatory bowel disease, heart disease, diabetes, and depression.
- If intestinal bacteria are responsible for the changes in the barrier structure of the intestine in old age, it may be possible to counteract these changes with probiotics.
A scientific article entitled “Effectiveness of Probiotics for Preventing Infections in the Elderly: Systematic Review and Meta-Analysis” was published in 2015 in the Nutrition Bulletin. It takes into account the fact that older adults are more susceptible to infections, often with serious consequences. Studies suggest that probiotics play a role in preventing infection in older adults.
Here are the key facts from the study:
- Older people are more prone to infection than younger adults, with symptoms generally severe and atypical.
- Infection is a major cause of early mortality in the elderly.
- Elderly people taking probiotic supplements for three months have a reduction in the average duration of infection and a reduction in the incidence of infectious diseases, particularly upper respiratory infections.
Stress weakens the immune system in old age
The American Institute of Stress (AIS) serves as a trusted source for all scientifically sound information on stress management. On their page you tell how chronic stress affects seniors and how you can deal with it.
Here are the most important facts at a glance:
- A weak immune system can no longer effectively resist bacterial infections and respond to inflammation, leading to osteoporosis, arthritis, type 2 diabetes, cancer, and dementia.
- Chronic stress is a cause of accelerated biological aging and therefore has a negative effect on the immune system and its function.
- Stress can greatly reduce the immune response to pneumonia in the elderly.
What do telomeres have to do with aging?
The telomeres are known as the clock of every cell’s life and determine our biological age. As tiny components of the DNA, they cover the chromosome endings like a kind of protective cap and thus prevent them from sticking together. However, with each cell division, these structures shorten and accelerate the aging of the cell. If the telomeres are too short at some point, the cell dies. This is why shorter telomeres are also associated with increased biological age.
The enzyme telomerase is responsible for maintaining the correct telomere length. However, a number of studies have shown an association between shorter telomeres or decreased telomerase activity and a variety of diseases, including cancer, heart disease, osteoporosis and HIV infection.
A 2008 study suggests that decreased telomere length is also linked to chronic psychological stress and mood disorders. The researchers also found that exposure of T lymphocytes to the stress hormone cortisol leads to a significant reduction in telomerase activity. The association between psychological stress and shortened telomeres has also been documented in studies on mothers of chronically ill children and carers of patients with Alzheimer’s disease. The complex interactions between the endocrine, nervous and immune systems can affect both mental and physical health.