Your immune system is your body’s own defence against infection. Medicine helps when it is needed, but a good deal of how well that defence works comes down to ordinary habits — what you eat, how you sleep, how much you move and how you handle stress.

None of what follows is dramatic. That is rather the point: small habits held consistently do more for immunity than anything you can buy in a bottle.

1. Eat a nutrient-rich diet

A balanced diet is the foundation. A few nutrients are worth knowing by name:

  • Vitamin C — an antioxidant that supports the production of white blood cells. Oranges, lemons, strawberries, capsicum and broccoli are all good sources.
  • Vitamin D — important for immune function, and easy to fall short on. Fortified dairy, fatty fish and egg yolks help, as does around twenty minutes of sunlight a day.
  • Zinc — involved in immune cell function and in controlling inflammation. Found in nuts, seeds, beans and meat.
  • Probiotics — gut health and immune health are closely linked. Curd, kefir and fermented foods feed the bacteria that do this work.

2. Stay hydrated

Water matters more than it is given credit for. Among other things, it helps your body produce lymph, the fluid that carries infection-fighting white blood cells around the body. Eight to ten glasses a day is a reasonable target for most adults.

Herbal teas count too. Ginger and green tea both carry antioxidants of their own.

3. Get enough sleep

Sleep is when the body repairs itself and produces cytokines, the proteins it uses to fight infection and inflammation. Cut sleep short often enough and you measurably blunt your ability to fight off illness. Most adults should aim for seven to eight hours a night.

4. Move regularly

Moderate exercise improves circulation, which lets immune cells travel through the body more efficiently. It also lowers inflammation and supports the production of antibodies and white blood cells.

Thirty minutes a day of walking, cycling or yoga is enough to matter. There is such a thing as too much, though — very intense training without recovery can work against you.

5. Manage stress

Sustained stress raises inflammation and dampens the immune response; cortisol, the main stress hormone, suppresses parts of it directly. Meditation, breathing exercises and mindfulness all help, and so does anything that reliably takes your mind off the day — reading, music, time outdoors.

6. Keep up basic hygiene

It sounds obvious because it is, and it still works better than most of the alternatives. Washing your hands properly with soap and water — particularly before eating and before touching your face — stops a large share of infections at the door. Clean living spaces and some distance from anyone who is unwell do the rest.

7. Supplement only where you need to

A balanced diet should cover most of what you need. Supplements are for filling a specific gap, not for insurance:

  • Vitamin C, if your diet is genuinely short of it
  • Vitamin D, which is worth considering if you get little sunlight
  • Elderberry, which is commonly taken for colds and flu

Do not start a supplement on the strength of a list like this one. Speak to your doctor first — dose matters, some supplements interact with prescribed medicines, and a blood test will often tell you in one step whether you need one at all.

In short

Nutrition, hydration, sleep, movement, lower stress and clean hands. Held together over months, these do far more for your resilience than any single intervention.

If you are falling ill more often than you think you should, or you feel persistently run down, that is worth a proper look rather than a change of diet — book an appointment and let a doctor rule out the causes worth ruling out.