“About a billion people around the globe suffer from a vitamin D deficiency. Since the two most important sources of vitamin D – sunlight and nutrition – are often unable to ensure an adequate supply, vitaminization of staple foods has come into the focus of discussion. The milling industry can play a key role in this respect. Premixes with vitamin D are a simple and efficient way of preventing the serious consequences of deficiency in large sections of the population. Five states have already issued mandatory requirements concerning the fortification of flour with vitamin D.”

A balanced vitamin D level is essential for human health and vitality. Whereas the significance of vitamin D for calcium and bone metabolism has been known for many years, more recent research has revealed that the fat-soluble micronutrient has a much wider range of influence on the body than previously assumed. A vitamin D deficiency is now known to be associated with diabetes, bowel cancer, anaemia, hypertension and multiple sclerosis, for example, as well as rickets and osteoporosis.

A lack of the “sunshine” vitamin Only an extremely small proportion of our daily requirement can be covered through our food. Apart from fatty fish, vitamin D is to be found mainly in eggs, offal, milk and dairy products and also in fungi.

A much more significant role in the supply of vitamin D is played by sunlight, since the body is itself able to synthesize this vitally important vitamin through the skin with the aid of UVB radiation.

However, this synthesis depends on a diversity of factors, for example the time of year and the time of day, the degree of latitude at which we live, the weather, our clothing and our skin type. Risk groups include women and girls who only go outside with their body completely covered, and dark-skinned people whose higher melatonin level in the skin blocks off most of the UVB radiation. The use of sunscreens also has a negative effect on the formation of vitamin D. A further problem is that the ability of the body to synthesize vitamins generally decreases with age. The conventional approaches to preventing vitamin D deficiency have so far failed to improve the situation sufficiently. In many cases, dietary recommendations that include a high consumption of fish, liver, eggs and milk are not feasible in practice. Extensive sunbathing is not to be recommended either, because of the risk of skin cancer. And the use of food supplements as a source of vitamin D is usually confined to a few individuals.

[box type="shadow" align="alignright" class="" width="300"]Flour is the medium of choice More and more nutritionists are therefore calling for re-orientation of the measures and turning their attention towards cereal products. In the past, flour fortification has mainly focussed on iron, folic acid, zinc and the B vitamins, but it is no problem to add vitamin D to the premixes, too. Since wheat flour is a staple food that has a particularly wide range of uses, large sections of the population could be reached by vitaminizing bread, biscuits, cake, pizza, pasta & Co., so the advocators argue.[/box]Growing awareness of the problem In other words: the undersupply of vitamin D to the population presents a major challenge – especially since vitamin D deficiency is a worldwide problem and not just restricted to certain regions. In Switzerland and Germany, for instance, it is estimated that half the population suffers from an often considerable vitamin D deficiency. The figure is similar for sunny Brazil, where around 60 percent of all adults are undersupplied with vitamin D. In some Indian states the figure is well above 80 percent, and even for Canada the estimate is meagre. Although the country has binding regulations on the fortification of milk and margarine, the vitamin D level of 32 percent of all Canadians is below the target value. In the USA, too, the situation is unsatisfactory: in spite of the widespread fortification of milk, orange juice and breakfast cereals, the provision of vitamin D is reckoned to be “inadequate” in a quarter of all consumers, and in eight percent it is even rated as “deficient”.

Rapid success with fortified flour In the literature we find several recent studies concerning the fortification of flour with vitamin D. In 2015, for example, the Department of Health in London published a British analysis based on simulated fortification with vitamin D. Since one person in five in the UK suffers from an alarming vitamin D deficiency, a theoretical model calculation was carried out to show how the health status of the population would change if both milk (up to a maximum of 70 μg/l) and bread (100 μg/kg flour) were to be fortified. On the basis of existing data it was possible to prove that vitamin D deficiency would fall from 93 to 50 percent in the groups at risk. Since the evaluation also showed that flour was more effective than milk, the team led by the nutrition scientist Dr Rachel Allen favoured the cereal rather than the dairy product. “The fortification of flour with vitamin D is to be recommended as an option for reliably improving the intake of vitamin D by the population”, was the conclusion reached by the study.

A Finnish study at the University of Helsinki demonstrated how quickly the vitamin D level in the blood can be raised by increased administration. For three weeks, four groups tested the effect of wheat or rye bread fortified with 120 μg of vitamin D per kilogram of bread. The result left no room for doubt: all the participants who consumed an extra portion of vitamin D through the fortified bread were found to have a significantly higher serum level of vitamin D. Only in the control group, that had been given conventional wheat bread, did the value remain unchanged. “The fortification of bread is therefore a practical means of raising the vitamin D status of all sections of the population. Moreover, the risk of overdosing can be practically excluded, since bread is only consumed in limited amounts”: this was the conclusion reached by the Finnish researchers.

According to the Food Fortification Initiative (FFI), five states have now responded to these requirements and introduced mandatory regulations on the fortification of flour with vitamin D. “Saudi Arabia, Oman, Palestine, Jordan and Kuwait are absolute pioneers in this field, says Sarah Zimmerman from the FFI, welcoming such commitment in the Middle East. The prescribed amounts vary between 0.013 and 0.015 ppm vitamin D, depending on regional eating habits.

Mühlenchemie tests stability and baking properties Vitamin D occurs in the form of different chemical compounds. For flour fortification, Vitamin D3 (cholecalciferol) is used – a particularly stable and effective form that can be stored in the human body longer than vitamin D2 (ergocalciferol), for example.

For many years, Mühlenchemie has been one of the most prominent suppliers of high-quality vitamin and mineral premixes. Following an increasing number of inquiries from customers on the subject of vitamin D, research scientists and applications experts at the company’s own Stern Technology Center carried out trials in order to determine the baking properties and possible loss of activity of vitamin D3. The product used was spray-dried vitamin D3 that had been stabilized with tocopherol to protect it against oxidation.

The products tested were vitaminized bread and biscuits, the usage level being 7.5 μg/kg flour. In terms of 100 g of the baked product, the vitamin fortification was therefore 15 percent of the Nutritional Reference Value (NRV).

The technologists were extremely satisfied with the results of baking. The powder was very finely distributed, proved to be easy to use and did not impair either the sensory attributes or the appearance of the end products. With regard to stability, the results differed between bread and biscuits.

In the case of white bread/sandwich loaves, the loss of activity measured was between 15 and 20 percent. The baking temperature was 200 – 210 °C, and the core temperature at the centre of the loaves during the 30-minute baking time reached about 98 °C.

In the case of the biscuits, the activity of the vitamin fell by about 30 percent. The reason for this was the slightly higher baking temperature and the small, flat shape of the pieces. The temperature at the centre of the biscuits was therefore much higher, which led to increased degradation processes.

However, such processing losses are taken into account from the start when flour fortification concepts are calculated. A corresponding increase in the prescribed usage level ensures that the necessary vitamins are still present in sufficient amounts after baking.

[box type="shadow" align="aligncenter" class="" width="350"]Consumers welcome a vitamin D boost

Vitamin D fortification in the milling and baking industries is still a niche market. But more and more food manufacturers are taking the subject up – not least in the wake of the “veggie boom”. Proof that an attractive unique selling proposition can be achieved with vitamin-enriched bakery products has been given by the British retail chain Marks and Spencer. Since 2015, a large proportion of the wrapped loaves and bread rolls has been enhanced with an extra portion of vitamin D. This measure was preceded by a survey carried out with some 2,500 consumers, 70 percent of whom were in favour of fortifying foods with vitamins in order to achieve the recommended daily intake. It is true that the vitamin D used by Marks and Spencer does not come from fortified flour but from a special baking yeast that produces large amounts of this micronutrient. But the promotional effectiveness is obvious: the vitamin D coup is advertised plainly on every pack. [/box]

*If you have any questions, please approach Lena Kampehl, product developer at Mühlenchemie. She can be contacted at: lkampehl@stern-wywiol-gruppe.de