Is taking extra vitamin C worthwhile?
Extra vitamin C offers little benefit for most people. Intensive athletes and people following a carnivore diet do have a good reason to supplement, and those who take it daily tend to have slightly milder symptoms when they catch a cold.
For most people, taking extra vitamin C offers little benefit. Large-scale research involving nearly 884,000 participants shows no advantage for heart disease or diabetes. A normal varied diet provides enough, and taking supplements on top of that adds little, unless you do intensive sport.
Marathon runners, soldiers and skiers had colds half as often in 5 studies when taking 1 gram of vitamin C or more daily. For people with an ordinary lifestyle, it does not work that way.
Do you want to try it to make a cold less severe? Take 1 gram daily as a preventive measure, and switch to 6 to 8 grams per day at the first signs of illness. In 15 studies involving more than 6,000 participants, the severity of symptoms was on average 15% lower with daily use. Two studies found that 6 to 8 grams per day made a cold shorter than lower doses did.
Whether starting after the first symptoms helps is uncertain: the studies contradict each other on this point. Liposomal vitamin C (in which vitamin C is encapsulated in tiny fat particles) is more expensive and too little studied to recommend.
More is not automatically better. Do you have haemochromatosis (iron storage disease)? If so, do not take vitamin C supplements, as this increases iron absorption. Do you eat only animal products? Then you are probably not getting enough and supplementing is genuinely worthwhile.
All claims are based on studies in people and many studies combined. Note: two authors of one study on immune support work at Bayer Consumer Care, a vitamin manufacturer. Read their positive conclusions about immune support with that potential conflict of interest in mind. The claims about brain health show a link, not a proven cause, and come from small studies.
Should I take vitamin B12 supplements as I get older?
Getting older increases the risk of a B12 deficiency, even if you eat healthily. A tablet of 1000 µg per day is safe and restores blood levels effectively; discuss this with your doctor. In addition to your B12 blood value, ask for your methylmalonic acid (MMA) level to be measured for a reliable picture.
Can you get too much vitamin D?
Too much vitamin D is genuinely harmful, but that risk only arises at blood levels far above the recommended values. Stick to the dose on the packaging, and if you are unsure about your level, have it measured by your GP.
Do antioxidant supplements make sense?
For healthy people, antioxidant supplements such as beta-carotene and vitamin E are not useful as protection against cancer or heart disease, and beta-carotene is frankly inadvisable for (ex-)smokers. The only well-supported exception is the AREDS formula for advanced macular degeneration: discuss this with your ophthalmologist.
Do tanning beds give you vitamin D?
A sunbed can raise your vitamin D level, but only if the light also contains UV-B, and most commercial beds emit very little of it. Because sunbeds demonstrably increase the risk of skin cancer, a vitamin D supplement is the safer choice.
Does liposomal vitamin C work better than regular vitamin C?
Liposomal vitamin C reaches higher blood levels than regular vitamin C, but whether that translates into real health benefits has not been proven. The higher price cannot yet be justified for most people.
Does vitamin C actually help against a cold?
Taking vitamin C daily does not protect most people against colds, but does make a cold somewhat shorter and milder. Intensive athletes benefit more. Anyone who really wants an effect during a cold would do better to look at zinc.