Riboflavin, also known as vitamin B2 as it was the second substance shown to be essential for human health (after Vitamin B1), is a water-soluble vitamin. It is the vitamin responsible for the yellow-orange colour of fizzy multi-B vitamin supplements and for turning your urine a bright yellow-green colour.
The word "riboflavin" itself comes from two roots - "ribose" (a sugar which is present in its reduced form, ribitol, to form part of the structure of riboflavin) and "flavin", the second part of the vitamin molecule which imparts the yellow colour (from the Latin flavus meaning "yellow").
Riboflavin performs many important functions. It
Riboflavin is related closely to energy metabolism.
The Recommended Dietary Intakes* (RDIs) for riboflavin per day are:
0.3 mg for infants (0-6 months)
0.4 mg for infants (7-12 months)
0.5 mg for children (1-3 years)
0.9 mg for children (9-13 years)
0.6 mg for children (4-8 years)
1.1 mg for girls (14-18 years)
1.3 mg for boys (14-18 years)
1.1 mg for women (19-70 years)
1.3 mg for women (>70 years)
1.3 mg for men (19-70 years)
1.6 mg for men (>70 years)
mg means milligrams
* (NHMRC Australia 2006)
This cannot be estimated precisely but 100 mg a day is considered a prudent maximum intake. That said, it is difficult to suffer from too much riboflavin because, being water soluble, any excess is excreted via your urine – hence the “day-glo” yellow effect commonly seen after taking B complex 50 or 100 mg supplements.
Riboflavin is not stored in the body, except for a small quantity in the liver and kidneys, so it is needed regularly in the diet.
Riboflavin is found in many of the foods that contain other B vitamins, notably milk, cheese, yeast, organ meats or offal such as liver and kidneys, whole (unrefined) grains e.g. millet and wild rice, mushrooms, and nuts, especially almonds. It’s one of the B vitamins commonly added to fortified breakfast cereals, malted milk powders and meal replacement drinks or diet shakes.
Here’s a list of the top 20 riboflavin-rich foods, both natural and fortified, ordered by concentration by weight per 100g/3 oz in descending order:
Source: NUTTAB 2010
Not much. Only a little of the riboflavin in foods is lost in the cooking water. However riboflavin is highly sensitive to light, which is why milk – a major source - is best stored in non-clear containers or away from light.
Riboflavin can be used as a natural orange food colour and you’ll see it on food ingredient lists as the additive number 101 (or in Europe as E101).
It’s relatively easy to get enough riboflavin as the vitamin is added to many cereals. Riboflavin is one of four vitamins added to most fortified products. Look for the word ‘RIBOFLAVIN’ under the Vitamins on the Ingredient List on a food label.
Most breakfast cereals are fortified with riboflavin at the level of 0.42mg per bowl or cup.
Smaller amounts in many different foods all add up over a day to meet your RDI. Refined foods such as sugar, oils and many processed foods have little or none.
20g Serve of All-Bran (0.2), 20g Special K (0.5), 100g Greek plain yoghurt (0.27) and 125ml reduced fat milk (0.27) | 1.24mg |
Bowl of 50g untoasted muesli (0.25) with 1 cup milk (0.6) and 25g almonds with skin (0.35) | 1.2mg |
150g grilled lamb (0.52), 1 cup steamed broccoli (0.37) and ½ cup grilled mushrooms (0.45) | 1.2mg |
Tub of 200g natural yoghurt full-fat (0.5) and 50g handful of almonds with skin (0.7) | 1.2mg |
2 large eggs (0.42) with 1 cup grilled mushrooms (0.6) and ½ cup spinach steamed (0.18) | 1.2mg |
Deficiency rarely happens on its own – it’s always accompanied by a deficiency of other water-soluble vitamins. Here are the telltale signs:
Severe riboflavin deficiency may result in decreased conversion of vitamin B6 to its coenzyme form and decreased conversion of tryptophan to niacin (vitamin B3).