Good sources of vitamin C include:
Not having enough vitamin C as part of your diet is the main cause of low vitamin C levels — as your body can't make it. But a deficiency is quite uncommon. You might develop a mild deficiency if you follow a poor or very restricted diet.
Symptoms of low levels of vitamin C include:
Vitamin C deficiency has also been linked to a weakened immune system, increasing your susceptibility to infections.
Extreme cases of vitamin C deficiency is called scurvy.
A balanced and varied diet should provide you with all the vitamin C you need.
If you do take a vitamin C supplement, don't take too much as this could be harmful. Less than 1,000 mg of vitamin C supplements a day is unlikely to cause any harm. If you take more than this a day, it can cause stomach pain, diarrhoea, and flatulence. It’s always a good idea to speak to your pharmacist or GP before starting any supplement.
Hemilä, H. (2017). Vitamin C and infections. Nutrients, 9(4), 339.
National Institute of Health (2020). Office of dietary supplements. Vitamin C: Fact sheet for health professionals. Retrieved 17 March 2020 from https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/.
National Health Services (2017). Vitamins and minerals: Vitamin C. Retrieved 17 March 2020 from https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-c/.