Intravenous vitamin injections: where is the evidence?

Key learning points

• Most people should be able to get all the vitamins they need from a healthy, balanced diet.

• Oral vitamin supplements are recommended for some people who are at risk from vitamin deficiency.

• There is some evidence for the use of intravenous vitamins for a few medical conditions.

• We are not aware of any high-quality outcome evidence of health benefits to support the use of intravenous administration of vitamins in the absence of vitamin deficiency or specific medical indications.

• Possible adverse events resulting from intravenous infusions include infection, allergic or anaphylactic reactions, hypotension, phlebitis, air embolism and fluid overload.

Introduction

Guidance from the National Health Service (NHS) states that most people do not need to take vitamin supplements and can get all the vitamins and minerals they need by eating a healthy, balanced diet.¹ Nevertheless, there are companies that offer intravenous administration of vitamins and their websites include details of a range of vitamin supplements that are administered by intravenous infusion. In addition, use of intravenous infusions of vitamins by high-profile individuals has featured in online articles with advocates suggesting that intravenous drips have the ability to help with energy levels, improve hangovers, support the immune system and treat illness.^{2 3} This article explores whether there is outcome-based evidence to support the use of intravenous high-dose vitamin supplements.

What are the daily vitamin requirements in adults?

The recommended daily vitamin requirements for adults aged 19—64 years and food sources providing these nutrients are shown in table 1.^4–6

Table 1

Daily vitamin requirements for adults aged 19–64 years and food sources^4–6

Nutrient	Food sources	Females	Males
Vitamin A (retinol)	Cheese, eggs, oily fish, fortified low-fat spreads, milk and yoghurt, liver and liver products*. Sources of beta-carotene (which the body can convert into retinol) include spinach, carrots, sweet potatoes, red peppers, mango, papaya and apricots	600 µg/day	700 µg/day
Vitamin B1 (thiamine)	Whole grain bread, fortified cereals, peas, bananas, oranges, nuts, liver*	0.8 mg/day	1.0 mg/day
Vitamin B2 (riboflavin)	Milk, eggs, fortified breakfast cereals, mushrooms, plain yoghurt	1.1 mg/day	1.3 mg/day
Vitamin B3 (niacin)	Meat, fish, wheat flour, eggs	13.2 mg/day	16.5 mg/day
Vitamin B6 (pyridoxine)	Pork, poultry, some fish, peanuts, soya beans, wheatgerm, oats, bananas, milk,...