Bread Matters: The sorry state of modern bread and a definitive guide to baking your own. Andrew Whitley
food to ensure the right nutrient intake across the whole population. But what if some people already consume a diet naturally rich in nutrients? Are they to be warned off these new foods in case they unwittingly overdose on something?
There is, in fact, a real risk of over-consumption of individual micronutrients. Marion Nestle estimates that industry-initiated additions of iron to the food supply may well be contributing to haemochromatosis (caused by too much iron), which affects at least a million adult Americans. In the case of folic acid, fortification of all flour (as is done in the USA) can lead to a problem, especially with elderly people, in which excessive intake of folate complicates the diagnosis of vitamin B12 deficiency. Too much added calcium is implicated in prostate cancer1 and a recent study links high intake of both iron and calcium with lung cancer2.
The mandatory addition of folic acid to flour has so far been rejected in the UK, but the government’s Scientific Advisory Committee on Nutrition now wants to see it implemented. The millers are happy to oblige, so long as the government picks up the tab. So we are faced with the unedifying spectacle of a milling industry that removes more than half the folate from wheat asking to be paid to put it back again in synthetic form. Nice work if you can get it.
The baking industry is keen on the principle of nutrification because it opens up rich new seams of product development and added value. Breads are now appearing enriched with extra calcium and iron, oestrogen from soya, omega-3 essential fatty acids from linseed and extra fibre from oats, peas or more exotic sources. Such additional ingredients may be of benefit to some consumers but they constitute only a fraction of the nutrients essential to human health, which can be readily obtained from whole grains, fruits and vegetables. And in any case, I cannot help thinking that the baking industry’s historical, and continuing, investment in low-cost white bread makes it an unconvincing advocate of dietary improvement.
As science has confirmed the dietary importance of whole grains, the baking industry has sought ever more ingenious ways to engineer their benefits into breads that have the same bland flavour and ease of production as standard white bread, though with a healthier margin of profit. A charitable observer might regard this as ‘doing good by stealth’, and there can be no denying that any replacement of missing nutrients is good. It is good, particularly, because by focusing on health, however partially, it acknowledges that your choice of bread does matter.
However, any such positive message is undermined in several ways. The industry is still reluctant to state clearly and unambiguously what goes into standard white bread and the extent to which it is nutritionally inferior to less processed alternatives. The strategy of nutrification takes power away from the consumer: the miller, baker or additive formulator controls the quantity and mix of extra nutrients in a loaf – with the result that people whose consumption patterns deviate from the average may end up with an inappropriate intake.
But all this tinkering with added ingredients conceals a much more fundamental reason why your choice of bread matters a great deal.
The slow route to health
Industrial bread is made far too fast.
Old-time bakers knew that if you left dough to ferment for a long time in the right conditions, ‘acids’ would ‘ripen’ your mix and produce a moister crumb and better keeping quality, as well as that indefinable bread flavour. In Germany, Poland and Russia especially, the cultivation of lactic and acetic acids in traditional sourdough fermentation was valued for the flavour and digestibility of the local (mainly rye) breads.
Most of us are rather amazed that mixing flour, yeast and water produces dough that rises and can be baked into light-textured bread. But this is only half the story. While yeast turns sugars released from the flour by enzymes into carbon dioxide and alcohol, lactic acid bacteria are also at work. If yeast is the exuberant entrepreneur of dough expansion, lactic acid bacteria are the thrifty housekeepers. Not only do they not compete with yeast directly for food, relying on different sugars for their sustenance, but they coexist in a more active way. Lactic acid bacteria use amino acids and peptides generated by yeasts and in turn enable the yeasts to produce more carbon dioxide, as well as making gluten more elastic. These modest functional effects are disdained in the high-tech world of chemical additives and bread improvers. But lactic acid bacteria can do much more than make stretchier dough. They can transform this dough into healthy food by:
Enhancing the nutritional properties of bread.
Making nutrients more ‘bioavailable’.
Counteracting certain ‘anti-nutrients’ in flour.
Lowering its glycaemic index.
Controlling potential spoilage organisms.
Neutralising the parts of gluten that are harmful to people with coeliac disease and other wheat allergies.
Industrial breadmaking does not allow sufficient time for lactic acid bacteria to develop in the dough.
Nutritional enhancement and bioavailability
More and more research is demonstrating the remarkable power of lactic acid bacteria, not just to control potentially harmful substances but also to enhance beneficial ones. For instance, sourdough rye bread has larger quantities of the antioxidant pronyl-L-lysine than breads made with an ordinary yeast fermentation3.
Sourdough fermentation has also been shown to more than double levels of folate, as well as enhancing levels of several other micronutrients and antioxidants4. Baking bread using the long sourdough process may make minerals, especially magnesium, iron and zinc, more available to the body5.
Counteracting anti-nutrients
Lactic acid bacteria play a part in neutralising substances in wheat flour that can limit nutrient availability to human consumers. The bran layers on the outside of the wheat grain contain important sources of minerals such as potassium, magnesium, iron and zinc, but the bran also contains considerable amounts of phytic acid, which inhibits the absorption of these valuable minerals and trace elements. Mineral deficiencies are widely reported in developing countries and even in France a survey revealed that 72 per cent of men and 77 per cent of women had magnesium intakes below the dietary guidelines. Wholemeal bread is one of the best sources of magnesium (it has three times as much as white bread) but much of this remains inaccessible unless the phytic acid (phytate) is neutralised. A recent French study demonstrated that the action of lactic acid bacteria in sourdough fermentations improves the nutritional quality of wheat bread by reducing the amount of phytate. Simple fermentation with yeast produced less than half the quantity of soluble (available) magnesium at the end of a four-hour period compared with the sourdough6.
All this raises serious questions about the bioavailability of important nutrients in fast systems such as the Chorleywood Bread Process. The industrial bakers are showing renewed interest in wholegrain cereals for their ‘healthy eating’ ranges. It looks as though their ultra-fast doughs will be unable to deliver all the expected (and aggressively advertised) nutritional goodies.
Glycaemic response
The production of acids by lactic acid bacteria can lower the glycaemic response (the speed at which food raises blood glucose levels) to sourdough bread. This is of potentially greater significance than any glycaemic effect attributable to the difference in fibre content between wholemeal and white breads. In view of the enormous public health implications of obesity and diabetes, a natural way of reducing the glycaemic index of bread should be of great interest to responsible bakers.
Spoilage