How long can the following dietary supplements be used continuously: vitamin C, vitamin B and magnesium? Should you take a break? I am 37 years old.
Answered by Olgica Velkovski Škopić, mag. pharm., Velika Gorica
Vitamin C it can be taken continuously, without a mandatory break. For daily intake in healthy adults, it is most reasonable to stick to a dose of 100 to 200 mg per day, rather than high doses without a clear reason. In Croatia, the recommended daily value is 80 mg, while the maximum allowed amount in a dietary supplement is 800 mg per day. This does not mean that it is necessary to take 800 mg per day, but that it is the regulatory maximum allowed in a dietary supplement on the market.
For vitamin B there is no single dose, because it depends on the composition of the preparation, i.e. whether it contains vitamin B1, B2, B3, B6, folic acid, B12, biotin and pantothenic acid. Low-dose B-complex can be taken continuously and without a mandatory break, but with long-term intake it is most important to pay attention to vitamin B6. The European Food Safety Authority (EFSA), the scientific body of the European Union that assesses food safety, states 12.5 mg of vitamin B6 per day as the upper safe limit for adults due to the risk of peripheral neuropathy. At the same time, in Croatia it is allowed that the dietary supplement contains up to 20 mg of vitamin B6 per day. That’s why the rule of thumb is: low-dose B-complex is fine, but “forte” preparations with higher doses of B6 are not a good choice for long-term use without professional supervision.
In Croatia, they are for B vitamins recommended daily valuesi.e. the maximum permitted amounts in the food supplement: vitamin B1 1.1 mg/25 mg, vitamin B2 1.4 mg/25 mg, vitamin B3 16 mg/35 mg, vitamin B6 1.4 mg/20 mg, folic acid 200 µg/600 µg, vitamin B12 2.5 µg/25 µg, biotin 50 µg/150 µg and pantothenic acid 6 mg/18 mg.
Magnesium can also be taken continuously, without a mandatory break, if it is well tolerated and if there is no kidney disease. A practical dose for healthy adults is usually 200 to 350 mg per day. In Croatia, the recommended daily value is 375 mg, and the maximum allowed amount in a dietary supplement is also 375 mg per day. The American NIH (National Institutes of Health) states 350 mg per day as the upper safe limit for magnesium from dietary supplements, and the most common side effect of higher doses is diarrhea.
The stated doses refer to healthy adults. In the case of pregnancy and breastfeeding, chronic diseases, kidney disease, oncological treatment or medication, the recommendations may be different, and then the intake must be coordinated with a doctor or pharmacist.
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