Multivitamins - Should we be taking them?


Written by Lena Matthews


Multivitamins. They sound like the easy, fix all solution to our diet. Just take one and you’re covered for the day. Well, that isn’t really the case.


In fact, multivitamins are intended as supplements to a diet. The majority contain 100% of the daily dietary requirements of vitamins and minerals, so eating a healthy diet in addition means you may be consuming more than needed. As attaining these vital nutritional components through food is more beneficial than turning to the pills, it is therefore important to take a food first approach.


Take the fat-soluble vitamin A for example: -

An egg provides 70% of the recommended daily allowance (RDA), 100g of baked sweet potato can provide 384.5% and consuming 42g of chicken liver can provide you with around 112.5% of the RDA (as liver is rich in vitamin A, the NHS recommend it be eaten only once a week).


However, too much vitamin A, especially while pregnant, can be dangerous. During pregnancy, hypervitaminosis A can cause malformations of the head, heart, brain and spinal cord in the unborn foetus, potentially resulting in neural tube defects such as spina bifida. For a non-pregnant person, hypervitaminosis A can present as orange skin discolorations and vision problems. The NHS recommends consuming no more than 1,500µg daily and consistently for very long periods of time as some research (1) suggests this may make bones more susceptible to fractures with age.


Vitamin A, along with other excess fat-soluble vitamins (D, E, K), is stored in the body. Contrarily, water-soluble vitamins (B vitamins and vitamin C) cannot be stored in the body, and so excess is peed out (that’s money literally going down the toilet!). So, getting enough from food is key. Vitamin C rich foods include broccoli (100g provides 89.2% of RDA) and brussels sprouts (84g provides 71.4% of RDA). B vitamins can be found in eggs, green leafy veg, fortified breakfast cereals, liver and dairy. For example, 300ml of whole milk provides 100% of the B12 RDA and 100g of cooked spinach contains approx. 73% of the folate RDA.


Multivitamins also cover our daily mineral needs, so again, having a healthy diet on top can be too much. For example, the iodine RDA can be met by consuming 300ml of cow’s milk (also contains 53% of the calcium RDA and 100% of the B12 RDA) or by eating 120g of haddock (2). Selenium requirements are 100% met with 2 brazil nuts and up to 83% of the RDA met with salmon.


Vitally, the food first approach provides fibre, while multivitamins don’t. Fibre plays a crucial role in digestion to prevent constipation and acts as a prebiotic to gut flora. Vitamin K and B vitamins are also made in the gut by specific bacteria of your microbiota (3)(4); therefore, it is equally important to consume a wide variety of foods containing prebiotics and probiotics to fuel your gut microbiome.


Multivitamins can come in different forms, including effervescent tablets. These may seem appealing; however, some may contain up to 1g of sodium which may be unsuitable for some and should be counted when maintaining the 6g/day salt recommendation.


Multivitamins in gummy/jelly form may contain sugar, so it is best to opt for ‘no added sugar’ alternatives.


Okay, but are there any exceptions?


Yes. There are some situations where taking supplements are appropriate. For example, those with dietary restrictions (e.g., veganism) may need specific supplements for specific deficiencies if it cannot be managed through diet. However, it is important to consult a qualified nutritional or medical professional if unsure. In the UK, it is advised to supplement with 10µg of vitamin D in the winter months due to a lack of sunlight. Finally, there are medical conditions (e.g., Crohn’s disease) where supplements are essential and are prescribed by a doctor or dietician.


So, do you still think a multivitamin is appropriate for you?


References:

  1. SACN Review of Dietary Advice on Vitamin A - GOV.UK (www.gov.uk)

  2. Iodine Food fact Sheet (bdahttps://www.bda.uk.com/resource/iodine.html.uk.com)

  3. Ramakrishna, B., 2013. Role of the gut microbiota in human nutrition and metabolism. Journal of Gastroenterology and Hepatology, 28, pp.9-17.

  4. Said, H., 2011. Intestinal absorption of water-soluble vitamins in health and disease. Biochemical Journal, 437(3), pp.357-372.

39 views0 comments

Recent Posts

See All