What is White Flour?
White flour is a food of vegetable origin.
"Bianca" is a generic adjective, used to emphasize the candid appearance due to the lack of fibrous residues in the flour.
White flour belongs to the III fundamental group of foods. In fact, from the nutritional point of view, it plays the primary role of carbohydrate and energy source.
By white flour we mean that based on soft wheat. Durum wheat flour is called "semolina".
Soft wheat is a herbaceous plant belonging to the Family of the Poaceae (graminaceae), Genus Triticum, Species aestivum (binomial nomenclature Triticum aestivum ).
The flour is obtained by grinding the raw seeds and, based on the level of refining (sifting), products with different characteristics can be obtained: whole wheat flour, type 2 flour, type 1 flour, type 0 flour and type 00 flour .
The lighter flour has an impalpable consistency and is that of type 00.
The yield of soft wheat in white flour is around 70%. The remaining 30% is made from bran, cruschello, germ and farinaccio.
At the end of the refining process, they remain:
- More carbohydrates
- Less lipids, proteins, fibers, mineral salts (ashes) and vitamins.
Consequently, white flour can be considered a food rich in "empty calories"; in fact it brings a lot of energy (thanks to the high content of carbohydrates), without supplying significant quantities of micronutrients.
Some experts or alleged ones claim that this nutritional composition of white flour is partly responsible for the collective tendency to obesity and metabolic pathologies.
To tell the truth, there are various types of white flour. These differ in some phases of the production mechanism and in the "strength" of the finished product (later we will explain what it is).
Among the most characteristic phases of the production cycle we remember:
- Bleaching (now disused)
- Enrichment: used mainly in the USA; serves to replenish the food with some nutrients lost during refining (for example magnesium).
Strength of Flour and Food
White flour is a common ingredient in western food.
It is the basis of bread-making, the production of pasta and sweet foods.
For industrial food applications, it undoubtedly boasts better physical characteristics than less purified flours, especially as regards strength.
However, the flours are not all the same and are produced "to measure" according to the application destination.
Strength is a physical characteristic of white flour. It mainly concerns the activation of gluten, a protein that allows the dough to rise.
NB. Gluten is a nutritional element that, when taken by intolerants, causes celiac disease.
The strength of the flour is classified with Chopin's alveograph and is expressed in a graphic called "alveogramma".
The reference parameters are the toughness index (abscissa), the extensibility index (ordinate) and the breaking point; the unit of measurement is work (W).
Based on strength (from 90 to 370W), white flour is destined for different food uses (biscuits, dry pastries, bread making and special products such as panettone).
Strong flours, such as Manitoba, are ideal for bread-making and in general for long-rising dough. The weaker flours can instead be used for the production of biscuits or unleavened products
It hurts?
As anticipated, under the nutritional profile, white flour is the subject of several controversies.
It is not clear whether the controversies have a scientific foundation or are the result of a sort of "collective hysteria".
Below we will briefly summarize the possible health implications of white flour.
Bleaching residues
Whitening is a process that reduces the natural pigment of white flour, increasing its whiteness.
It is an old practice and no longer used. It was based on the application of some chemical substances such as: nitrogen oxide, chlorine, benzoyl peroxide, salts etc.
Chemical bleaching can leave residues and harm consumers' health. However, to date it should not be a cause for concern.
As specified in the regulation for the regulation of flour and bread-making, the European Union totally abolished this practice already at the end of the 1990s.
As a matter of informative correctness, we will now explain the reason for a similar correction. Chlorine oxide, interacting with some amino acid compounds, tends to form oxalane . This unwanted element has a harmful effect on the pancreas and can promote the appearance of diabetes.
This explains why (regardless of the actual concentrations of oxalane in the finished food) the bleaching has been eliminated from the flour production cycle.
Obesity and Metabolic Pathologies
It is said that white flour predisposes to obesity and metabolic pathologies.
This statement represents a distortion of the concept of glycemic index. Being a fairly complicated subject, we will simplify the information to the maximum, making it understandable:
- As anticipated, white flour has more carbohydrates and less fiber, protein and fat
- The "purity" facilitates digestion and speeds up the absorption of glucose
- As blood sugar levels rise (blood glucose), the pancreas reacts by releasing insulin
- Insulin is an anabolic hormone, which promotes the growth of tissues and energy reserves (including fat).
It should therefore be specified that, compared to an integral product, white flour:
- Contains more carbohydrates, about 9-10g more every 100g of food.
- With the same portion, increase the glycaemia more (glycemic load)
- It is more caloric, more or less 20kcal more per 100g of food.
- Contains less fiber, protein and lipids (about -6g, -1g and -1g).
- If the load and the glycemic index increase, the insulin index also increases. Insulin is the hormone responsible for transporting glucose to most tissues (for example muscle).
- The glycemic index of white flour is about 30-40% higher than the integral. This is due to the lower presence of fibers, proteins and lipids in the refined product.
To reason about the harmful potential of a food it is first of all necessary to establish the average portion of consumption.
Portions of food must meet the nutritional balance criterion. It is never correct to eliminate or exceed the quantities; for example, the average portion of pasta fluctuates between 70 and 90g.
Wanting to estimate the differences between white and wholemeal flour on a portion of pasta, the controversy would stop here. The metabolic impact is almost identical.
On the other hand, we must strive to have a broader view and consider the collective tendency to abuse food containing white flour; above all: bread, pizza, pasta, sweet snacks, cakes etc.
By abandoning the concept of nutritional balance and considering a high-calorie or unbalanced diet, the choice of flour could have a noteworthy impact.
Taking a trivial example, consuming 500g of white flour a day rather than wholemeal would result in the following differences:
- 45-50g more carbohydrates
- 100kcal more
- 30g less fiber
- 5g less protein
- 5g less lipids
HYPERGLYCEMIA
In addition to facilitating weight gain (due to increased adipose tissue), hyperglycemia has many negative health effects. Among these, above all the tendency to type 2 diabetes mellitus, hypertriglyceridemia and other metabolic pathologies.
Chronic hyperglycemia decreases tissue sensitivity to insulin. Not receiving glucose, the tissues continue to ask pancreatic insulin, which increases their blood levels. In the long term, this organ becomes tired and reduces its functionality, giving rise to diabetes and its complications.
Moreover, hyperglycemia has a negative effect on the function of blood transport proteins. Due to the so-called glycation, the structure of the peptides is altered, which lose efficiency and effectiveness.
In particular, this reaction appears to compromise the functionality of lipoproteins (cholesterol transporters). When they are glycated, the lipoproteins do not interact correctly with the receptors and remain too long in the circulation, oxidizing (due to the action of free radicals).
This occurs mainly with LDL or bad cholesterol, responsible for fatty deposits in the arteries and atherogenesis phenomena.
These metabolic complications occur mainly in conditions of: obesity, overeating, unbalanced diet, sedentariness, genetic predispositions and combination of other factors.
- If the diet has few calories, the use of the whole promotes the achievement of many nutritional levels; among these above all the fibers, some vitamins and certain mineral salts.
- On the contrary, if the diet is very abundant (for example, in the case of a professional athlete), the use of whole wheat flour could induce the surplus of fibers and compromise the intestinal absorption of some nutrients.
Celiac Disease and White Flour
White flour contains less total protein, but more gluten than whole wheat.
Gluten is a polypeptide based on glutenin and gliadin. The two proteins are normally independent in the whole cereal but, after grinding and mixing with water, they are activated forming an elastic net. This imprisons the gases released by leavening (natural or chemical) and grows increasing in size (volume).
In intolerant individuals, gluten can trigger unwanted and serious long-term reactions. This intolerance is called celiac disease and - with the onset of complications due to gluten intake - gives rise to celiac disease.
Celiac disease is a very specific condition, although sometimes it manifests itself atypically. It should not be confused with NOT diagnosable pictures, some of which are probably based on psychosomatics (autosuggestion).
Celiacs must totally and definitively exclude gluten from the diet (therefore all wheat-based foods). In this case, white flour is neither more nor less harmful than wholemeal flour.
White flour and intestine
Many believe that the use of white flour is related to bowel disorders.
Among the most involved disorders there would be:
- Irritable bowel syndrome: it is not dangerous and manifests itself with various symptoms, sometimes very different. The most common are: abdominal cramps and pain, diarrhea, constipation and nausea.
- Inflammatory bowel disorders: ulcerative rectal colitis and Crohn's disease. They can also be very serious and cause permanent complications.
QUESTION
"Are these disorders caused or aggravated by eating white flour?"
The answer is no". At least, not directly.
At the moment we ignore the existence of molecules that play a decisive role in the onset of the aforementioned diseases.
Some suspect the involvement of gluten, especially with regard to irritable bowel syndrome. On the other hand, this would not only concern white flour, but any cereal derivative containing the protein in question (wheat, spelled, spelled, rye, oats, sorghum and barley).
With regard to chronic intestinal diseases, if the responsible etiological agent was white flour, the cure would be much more decisive than what happens. These pathologies still have a rather obscure origin and it seems that one of the main causes is an autoimmune reaction.
Let us not forget, however, that inflammatory bowel diseases correlate positively with celiac disease. In this sense, gluten would undoubtedly worsen the symptoms and increase the possibility of acute.
It could however be stated that white flour is NOT the most suitable food for the treatment of certain intestinal problems. In fact, the prevention of intestinal problems is almost always based on the abundance of fiber in the diet (especially soluble); the only exception is diarrhea.
These fibers prevent constipation, keep the intestine clean and feed the bacterial flora. In turn, these physiological microorganisms participate in the healthy maintenance of the mucosa of the large intestine and contribute to the immune balance.
Despite being richer in fiber, whole wheat flour contains especially those that are not soluble. Even in this case, replacing the white flour with the unworked one could be a positive but not decisive element.
Finally, we recall that some intestinal problems (such as the acute forms of inflammatory diseases) cause severe diarrhea and require a diet low in fiber (with low residue or with little waste). In this case, white flour could even be more recommended than wholemeal flour.
