Immune System and Gut Health: Understanding the Connection

Important vitamins for immune health:*

• Vitamin C
• Vitamin D
• Vitamin A

Important mineral for immune health:*

• Zinc

Herbs & other supporters of immune health*:

• Echinacea
• Quercetin

When do babies develop an immune system?

The development of an infant’s immune system is a fascinating topic about which scientists are still learning.

During the third trimester of pregnancy, the mother shares an immune system with her baby by passing antibodies through the placenta. This is called “passive immunity,” because the baby is given antibodies from the mother instead of making them on its own.¹

This passive immunity continues to protect the infant for the first few weeks or months of its life, depending on the mother’s immune system and antibodies. Breast milk also contains antibodies, which means that babies who are breastfed will have passive immunity longer than formula-fed babies.

Premature babies are at a greater risk of infection than babies born at full term because they haven’t had as many antibodies passed to them from their mothers.

After a few weeks or months, babies begin to develop “active immunity,” which refers to the antibodies they develop when exposed to antigens. It takes time for an infant’s immune system to fully develop.²

How much of your immune system is in the gut?

Approximately 70% of the body’s immune cells are housed in the gut. The immune and digestive systems interact closely, and supporting your gut health can lead to improved immune health as well.

Read more: How the Digestive System & Immune System Work Together

How does vitamin C help the immune system?

Vitamin C is an essential micronutrient for humans, but the body cannot make vitamin C on its own. You need to consume vitamin C through external sources, such as through your diet or supplements. Like the B-complex vitamins, vitamin C is water-soluble. Because our bodies don’t store water-solubles well, vitamin C needs to be replenished every day.

Vitamin C, as ascorbic acid, is on the World Health Organization Essential Medicines List because it is needed by so many parts of the body. Vitamin C is involved in collagen formation which contributes to healthy skin and connective tissue.*

Vitamin C helps support the immune system by supporting various functions.* It is a potent antioxidant and helps fight oxidative stress which is important for a healthy immune response.* It also supports the functioning of white blood cells, which are major components of the immune system.*

Can your mental health affect your immune system?

The connection between mental and physical health is endlessly fascinating. In fact, there’s a whole field of psychology known as “psychoneuroimmunology,” which explores how your state of mind affects your immune and physical health.

The link between stress and immune health is widely accepted, and the link between depression and suppressed immune health is also becoming evident. Research shows that chronic feelings of loneliness can help to predict health status. This is perhaps because lonely people have more psychological stress or experience it more intensely and that stress tamps down immune health.³

When stressed, depressed, anxious, or suffering from other mental health struggles, you are also less likely to do the things that support immune health, such as eating a balanced diet, exercising, and getting adequate sleep which can, in turn, make your immune health suffer.⁴

Read more: 4 ways stress affects your health, and how to cope