Some time ago I wrote about a letter in J Biol Chem and referred, off-hand, to a paper on the Nutritive Properties of the Mung Bean. I am now returning to the Mung Bean [PDF]. Mung beans are not just for hippies and Gillian McKeith. No, “the growing popularity of chop suey and other articles of diet which contain as their principal constituents the dry or germinated mung bean, lends an interest to the nutritional value of this bean” – and this interest “is enhanced by the possibility of its growth in certain semiarid sections of this country [The US] where the short growing period makes the production of many of the popular articles of diet, for both man and animal, impossible”. Brilliant – far more interesting than any nutritionista nonsense. The growing popularity of the mung bean referred to in this opening passage does relate to 1927, but I’m sure Channel 4 viewers are still just as excited about mung beans nowadays thanks to McKeith insistence that the mung bean is an “abundance food” that “will help make you feel stronger and more energised, without getting fat or piling on the pounds” [abundance food list].
Of course, there’s nothing wrong with including these beans in your diet – I’m just not so sure that any food can be fairly said to make you feel stronger and more energised (and without getting fat or piling on the pounds, don’t forget). Firstly: we obtain energy from food, but this doesn’t mean that we necessarily feel more energetic after eating. I think that two meanings of ‘energy’ may be being conflated here – the general, colloquial meaning of energy as “get-up-and-go”, vim, or vigour and the meaning of the same word when used in physics, referring to a physical quantity that is measured in calories and joules. When I re-read this section it somehow didn’t seem like something I would write. I realised that the reason for that was probably that I had previously read something similar – and here it is: Boots and CoQ10. McKeith is apparently making the same claims for mung beans as Boots made for Coenzyme Q10. They are both wrong.
As for the seeming guarantee that you can eat mung beans and not put on weight, the USDA nutrient database tells me that raw mung beans contain about 350 Calories [Kcal] per 100 grams and the cooked bean contains 105 Calories per 100 grams. The raw beans are over 60% carbohydrate and contain 347 Cal per 100g – it seems to me that anyone consuming sufficient mung beans will put on weight, as their daily caloric intake will at some point exceed their daily caloric expenditure. It would also be a mistake to assume that only fat intake will lead to the body storing fat in tissues, as the same thing happens when consuming carbohydrates. “The excess glucose in the bloodstream is then sent to the liver and various muscle tissues where it is converted into glycogen, fat and other materials needed by the cells of the organism”, according to an article in the Encyclopaedia of Life Sciences that is available via Wiley Interscience (Polysaccharides: Energy Storage, by John F Robyt). [There’s a link to it here: polysaccharides-and-energy-storage] Anyway, that’s quite enough about McKeith. Back to the mung research:
The conclusions of the paper are interesting – including that “limited cooking seems to aid the nutritional value, while extensive cooking becomes detrimental” and that “the indications are that the mung is a superior type of bean from a nutritional standpoint, but not adequate as a sole source of protein”. These are observations familiar to me from more modern writings – for example, lycopene is said to be more bioavailable when cooked. Although whether lycopene is significant as a nutrient is another matter entirely – it seems the supposed benefits of lycopene don’t necessarily show up in trials and you may be better off, gasp – eating tomatoes. Which made me think of a new slogan – food is better medicine than supplements. I might ask Patrick Holford whether he wants to use that as a title for his next book.
The second conclusion I quoted seems to indicate that a major concern in 1927, as now, was the consumption of a balanced and sufficiently varied diet. The mung bean was deemed to be “superior as a bean, but not adequate as a sole source of protein.” The authors at no point, however, referred to mung bean as an abundance food – or a superfood. This is clearly at odds with modern nutritionism as practised by Gillian McKeith, but fits well with advice of modern dieticians.
So, what do I know? I know that mung beans, while nutritious, will not “energise” you. I know that McKeith makes silly claims about foodstuffs. I know that one reason these beans were of interest in 1927 is horticultural, whereas today’s interest in the same beans is probabl cultural. I know I love J Biol Chem (still).