Kamal Patel is a director of Examine.com, the research-based resource on supplementation and nutrition, and a nutrition researcher with an MPH and MBA from Johns Hopkins University. He is based in San Francisco, California.
A healthy immune system is the key to a long and happy life, but in the short-term the better your ability to fight off common bugs and viruses the less time you’re likely to be laid up in bed when you’d rather be in the gym.
To function efficiently the system needs to be able to identify and combat a wide rage of pathogen agents, ranging from simple to complex viruses, bacterias and parasites. Taking regular exercise, adhering to a good diet and getting adequate sleep are important considerations to have the best immune system possible, but there are also a variety of supplements you can take to bolster your natural defences, both to prevent the onset of illness and to reduce the duration and intensity of symptoms should you fall ill. Here’s what we know.
Garlic has been used by humans for more than 7,000 years and the Ancient Egyptians knew of its medicinal benefits. Garlic can improve the ability of white blood cells to destroy pathogens, in a process called phagocytosis. It also increases the production of T-cells, another one of the body’s defences.
Thanks to these two properties garlic can reduce the risk of infections and the common cold by as much as 60%, but it is mostly a preventative supplement that might reduce the severity of symptoms or the duration of illness.
Garlic may interact with several medications, including pharmaceuticals used to treat tuberculosis and HIV. It can also decrease the effectiveness of oral contraceptives. And talk to your doctor about garlic supplementation if you are taking medication, particularly blood thinners, such as warfarin.
Garlic can be supplemented or eaten in its natural form, with three cloves of garlic, eaten with meals throughout the day, providing maximum benefits, although it won’t win you many new friends. If you chose to eat it directly then garlic must be crushed or cut before it is heated to release the bioactive compounds.
How to take it To supplement garlic, take 600-1,200mg of aged garlic extract, split into multiple doses and taken with meals. Aging garlic preserves its benefits while eliminating the scent.
Vitamin C is hailed as the go-to supplement for those suffering from the common cold and has the most research on it in the context of alleviating upper respiratory tract infections, such as the common cold.
When taken as a daily preventative by sedentary people it can ward off colds, yet taking high doses at the beginning of an illness will not reduce the severity of symptoms.
owever, the research suggests that it can reduce the duration of illness and the frequency of a cold when supplemented by very physically active people, although the exact reasons for this are still unknown.
How to take it To supplement vitamin C, take 1,000-2,000mg a day over multiple doses. Further research is needed to determine if vitamin C is more effective when taken with a meal.
It’s worth nothing that vitamin C should be supplemented several hours after aluminium-based antacids because it can increase the absorption of iron and aluminium.
Pelargonium sidoides, also known as African geranium, is an herb containing compounds called prodelphinidins, which can prevent bacteria from attaching to the throat and lungs. Supplementation is used primarily to treat acute bronchitis, but taking it at the beginning of illnesses characterised by dry and hoarse coughing can reduce symptom severity and illness duration.
However, current evidence suggests supplementation is not capable of actually preventing illness and further research is needed to determine if taking Pelargonium sidoides as a daily preventative supplement is effective. Supplementation should begin at the onset of dry respiratory symptoms and continue for up to five days or until symptoms disappear.
How to take it Over three daily doses take 800mg of the dry plant weight, which is equivalent to 10-30 drops (1.5-4.5ml) of the liquid tincture form, assuming a 11% ethanolic extract, or 30-90mg of an 8-10:1 ratio concentrated powder. If taking capsules aim for 10–30 mg three times a day.
More commonly known as Guduchi, this herb has been used in traditional Indian medicine to stimulate the immune system. It is effective at alleviating the symptoms of allergies, such as a stuffy nose and, as with garlic, it can improve the ability of white blood cells to fight invaders. However, further research is needed to determine whether garlic and Tinospora cordifolia are synergistic if taken together, or whether supplementation can prevent infections.
How to take it To supplement Tinospora cordifolia, take 900mg of a water extract concentrated for 5% bitters, divided into three daily doses of 300mg.
Spirulina is a protein-rich algae that contains several bioactive compounds with anti-inflammatory effects. Though further research is needed to determine whether spirulina can ward off sickness, low doses of daily spirulina has been shown to alleviate the stuffy nose and sneezing that comes with allergies.
How to take it Take 2g daily for at least twelve weeks and it can be taken with meals.
Zinc is a hugely important dietary mineral for health, and it can bolster the immune system and protect against the common cold and other infective diseases. Supplementation, if started at the first sign of symptoms, has been noted to reduce the length of sickness and may prevent symptoms from getting worse.
The only studies to have found benefits for sick people supplementing zinc use high-dose lozenges, which can cause minor nausea and a temporarily disrupted sense of taste. Because of a lack of evidence supporting benefits of zinc nasal spray over lozenges, and possible permanent loss of taste from the spray, it is not recommended under any condition. Oral and lozenge supplementation of zinc can reduce the absorption of certain antibiotics, specifically quinolone and tetracycline formulations.
How to take it To supplement for an acute response to infective sickness, take 75mg of zinc lozenges, split into several doses throughout the day. Supplementation at this dose should stop as soon as symptoms disappear.
How to take it This herb was one of the first marketed as an immune system booster but, although widely used, there is not a lot of consistent evidence for its effects. Echinacea supplementation can reduce the risk of upper respiratory tract infection, and can reduce the length of sickness if taken as a daily preventative. However, the effects are unreliable.
Echinacea contains a variety of bioactive compounds called alkylamides, much more research is needed before it can be specifically recommended for allergy and immunity- related supplementation. Echinacea may interact with many drugs so talk to your doctor about supplementation if you are currently on prescribed medication. Do not supplement echinacea if you are taking immunosuppressive medications.
More research is needed to determine the optimal dose of echinacea, and to determine if it is more effective when taken with food or on an empty stomach.
How to take it Our current recommendation are to take 300–500mg, three times a day, for a total daily dose of 900–1,500mg. To supplement using a liquid tincture, take 2.5–10ml, three times a day, for a total daily dose of 7.5–30ml.
Smart supplement stacks
Putting together a supplement stack to improve immunity begins with a base of garlic and vitamin C, at the dosages recommended above.
If you begin to feel the onset of symptoms associated with a common cold, take the base of garlic and vitamin C, throughout the duration of the illness, and add zinc lozenges but only until symptoms start to disappear.
If you are suffering from the first signs of a respiratory sickness, characterised by a dry throat and a hoarse voice, then in addition to the base, add Pelargonium sidoides until symptoms disappear.
If you have a nasal allergy or stuffy nose-type symptoms, then take the base supplements, and add spirulina if your condition doesn’t improve. If symptoms persist after a month of supplementation, add Tinospora cordifolia.