Lactose em alimentos industrializados : avaliação da disponibilidade da informação de quantidade Lactose in processed foods : evaluating the availability of information regarding its amount

Resumo Indivíduos com intolerância à lactose, doença de alta prevalência, devem controlar o consumo de alimentos com esse dissacarídeo para evitar sintomas gastrointestinais. Como a tolerância é variável à quantidade ingerida, é fundamental a discussão sobre a disponibilização da informação de quantidade de lactose em alimentos industrializados, que atualmente não é obrigatória. O estudo avaliou a disponibilidade da informação sobre a quantidade de lactose por análise dos rótulos de alimentos industrializados, que contivessem leite ou lactose na lista de ingredientes. Em seguida, realizou-se contato com as indústrias de alimentos para solicitação da informação. Foram avaliados 1.209 alimentos, dos quais 1.092 eram tradicionais e 117 diet/light/zero. Apenas 3,1% dos alimentos analisados apresentavam a informação sobre a quantidade de lactose na tabela nutricional dos rótulos. A presença desta informação foi maior no grupo de alimentos diet/ light/zero do que nos tradicionais. Além disso, das 156 empresas contatadas, somente 14 informaram a quantidade de lactose contida nos alimentos, 93 responderam a solicitação, porém não disponibilizaram as quantidades, e 49 não responderam. Conclui-se que há baixa disponibilidade da informação sobre a quantidade de lactose em alimentos industrializados. Palavras-chave Lactose, Intolerância a lactose, Direito do consumidor, Rotulagem nutricional Abstract Patients with lactose intolerance, a high prevalence disease, should control the intake of food with lactose to avoid gastrointestinal symptoms. Since tolerance depends on the amount of lactose ingested, it is essential to discuss the availability of the amount of lactose information in processed foods, which is currently not mandatory. The study measured the availability of information on the amount of lactose on the labels of processed food that contained milk or lactose in the ingredient list. Then, we contacted the food industry to request this information. We evaluated 1,209 processed foods, of which 1,092 were traditional and 117 were diet/light/zero. Only 3,1% of the analyzed foods provided information on the amount of lactose in the labeled nutrition table. This information was more available in the diet/light/zero food group. Furthermore, of the 156 contacted companies, only 14 reported the amount of lactose contained in foods, 93 answered the request, but have not provided the amounts and 49 did not answer the request. We concluded that there is a low availability of information about the amount of lactose in processed foods.


Introduction
Lactose is the primary carbohydrate found in milk.It consists of two monosaccharides, glucose and galactose, characterizing a disaccharide.Lactose intolerance consists of poor digestion and absorption of lactose from the reduced activity of the β-galactosidase enzyme, also known as lactase, which can hydrolyze lactose to glucose and galactose 1 .Individuals with lactose intolerance are unable to digest lactose, which will not consequently be absorbed into the small bowel.When reaching the colon, lactose is fermented, producing short-chain fatty acids and the formation of gases (carbon dioxide, hydrogen and methane) by the intestinal microbiota 2 , which can cause gastrointestinal problems, discomfort and symptoms, such as nausea, colic, flatulence, diarrhea, bloating, abdominal pain, among others 3 .Usually, these symptoms start around 30 minutes to 2 hours after consumption of some food containing lactose 4 .
Lactose intolerance can be classified into three types: congenital, primary and secondary.The congenital is caused by the complete absence of jejunal lactase throughout the life of an individual and is detected at childbirth.The primary type can develop at any age and is caused by the declining concentration of lactase in the human body, genetically programmed (non-persistent lactase), from infancy to adulthood, leading to difficulties in the hydrolysis of lactose.The secondary type occurs due to the presence of intestinal lesions or diseases and is transient and reversible 5 .
The persistence of lactase (or lactose tolerance) in different populations seems to be associated with the domestication of dairy cattle and with the habit of consuming milk after weaning 6 and, therefore, the prevalence of lactose intolerance varies according to the geographic region and habits of the population.
A study points that non-persistence of lactose, or lactose intolerance, is found in 65% of the world's population 7 , affecting around 2% to 15% of people of North European descent, 60 to 80% of blacks and Latinos, and 80% to 100% of Native Americans and Asians 5 .In Brazil, a study showed that the prevalence of primary lactose intolerance in adults in a sample of 567 subjects was 57% for whites and mulattos, 80% for blacks and 100% for Japanese 8 .Other studies indicate a high prevalence in the Brazilian population: 44.1% in 1,088 individuals in Southern Brazil 9 and 60.8% in 115 individuals in Southeast Brazil, of which 53.2% in whites and 91.3% in nonwhites 10 .
A reduction of at least 50% of enzyme activity is required to trigger the symptoms resulting from the primary deficiency of lactase, which explains part of the variation in tolerance to small doses of lactose by individuals with lactose intolerance.Another possible explanation is the adaptation of the intestinal microbiota 11 .
Studies show a variation in the amount tolerated between 7 and 15g of lactose per day [11][12][13] .A study conducted by Vesa et al. 14 , showed that individuals with lactose poor digestion did not evidence gastrointestinal symptoms induced by the ingestion of low amounts of lactose (0.5 to 7.0 g/day).
Therefore, concerning nutritional treatment, it is recommended to avoid the consumption of products containing a high amount of lactose or to perform the ingestion of the enzyme lactase with dairy products.It is also possible to consume dairy products in which the amount of lactose has been reduced by fermentation, such as yogurt or curds, or excluded by industrial processes, such as processed foods without lactose 15,16 .The inadequate nutritional planning or replacement of milk and dairy products with their respective lactose-free products may lead to a lower intake of calcium, phosphorus and vitamins 15 .
There is evidence of a high consumption of processed foods in contemporary society 17 , and a stimulus to the intake of diet/light/zero foods 18 .Thus, because of the tolerance of a certain amount of lactose by individuals with lactose intolerance, information on the presence and amount of lactose in processed food labels should be mandatory in Brazilian legislation on nutritional labeling of packaged foods.However, such legislation does not require the provision of such information 19 .
According to the National Health Surveillance Agency (ANVISA), lactose-free or low-lactose products should be labeled according to the specific regulations for special-purpose foods 20 .However, even if classified as such, the ordinance does not provide for the possibility of using a notice on the front label, clearly informing the consumer that the product is lactose-free or that it contains a low amount of lactose 1 , with the exception of processed soy-based food that, according to RDC 91/2000 21 , must state the following information: "Contains lactose", "Contains milk proteins" or "Contains lactose and milk proteins".
This study is justified by the need to map the availability of information on the amount of lactose in processed foods, since people affected by the lactase deficiency have difficulty in choosing foods to control the symptoms and often exclude them without necessity, which may compromise their health-related quality of life, which refers to the impact of the intervention, i.e., food restriction on the perception of well-being 22 , and its nutritional status.Also, failure to report the amount of lactose hampers the nutritionist's calculation of diets and nutritional orientation of lactose-intolerant patients.Thus, the aim is to evaluate the availability of information on the amount of lactose in processed food labels and by the Customer Service Department (SAC).

Methods
This is a cross-sectional and quantitative observational study evaluating the availability of information for the population of the amount of lactose in traditional processed and diet/light/zero foods marketed in a hypermarket in the city of Uberlândia, Minas Gerais.The hypermarket was intentionally selected because it has an abundant supply of processed foods and is considered the second largest supermarket company in Brazil 23 by the Brazilian Supermarket Association (ABRAS).
The evaluation was carried out in two stages.In the first, a diagnosis was made concerning the presence of information on the amount of lactose in the labels of processed foods.In the second, food industries were contacted, when this was free, over the telephone, by e-mail or through company websites to request information on the amount of lactose in their products, clarifying that this information would be used for scientific research.
Data was collected in 2015, following a written authorization by the hypermarket's management.Information included processed foods that contained milk or lactose in different positions in the list of ingredients, of different brands and flavors.Foods with the above characteristics, with the same composition, but with different packaging sizes, were excluded.It is worth noting that the position in the list of ingredients indicates, in decreasing order, the amount of the ingredient in the final product of the processed food, that is, the ingredients with higher amounts 24 appear in the first positions.
The information was collected in this study by an instrument pre-tested by the researchers, with a sample of 20 foods to define the following items: technical name; trading name; brand; telephone or e-mail of the customer service (SAC); position of lactose or milk in the list of ingredients; portion in grams and nutritional composition.
The foods were divided into two groups: traditional and diet/light/zero.In the latter, only diet foods were included, for nutrient-restricted diets or for controlled ingestion of nutrients (considered special purpose foods) 20 or with supplementary nutritional information (light, which is one with reduction of some nutrient compared to traditional and zero, which does not contain a particular nutrient) 25 .Each group was subdivided into 17 and 11 categories, respectively, according to the Brazilian Food Classification System 26 .
Following data collection and entry, a review of the information entered by two other researchers was carried out and descriptive statistical analysis was performed on the number and percentage of the results obtained.The comparison of the percentages of the declaration of the amount of lactose between traditional and diet/ light/zero foods was performed using the chisquare test, with a significance level of 5%.The GraphPad Instat software version 3.05 was used for statistical analysis.

Results
The total sample of processed foods was 1,209, of which 1,092 (90.3%) were traditional foods and 117 (9.7%) corresponded to diet/light/zero foods.Foods properly classified and included in the analysis are described in Chart 1.
The total percentage of the declaration of the amount of lactose in the nutritional table of processed food labels was 3.1%.The declaration was more frequent (p < 0.0001) in the diet/light/ zero food group (30%) than in the traditional food group (0.2%) (Table 1).Among the products that reported the amount of lactose (n = 38), 36 (95.0%) were diet/light/zero, of which 30.6% stated that the amount of lactose was equal to zero, and the remaining 2 (5.0%) were traditional foods.
Table 2 described foods that contained the milk in the first two positions of the list of ingredients and that probably are foods with a more considerable amount of lactose.Processed foods with the highest frequency of milk/lactose in the last positions in the list of ingredients and those that did not have a significant number of foods within the same category were not shown.
Among the foods that presented lactose as the main ingredient in its formulation, the most important are the infant formulas, in which 50% contained lactose in the first position (n=8) and 19% in the second position (n = 3).
Of the 257 food industries responsible for the production of food evaluated, 156 (60.7%) provide access to the free SAC and were contacted.Among them, only 14 (9.0%) reported the amount of lactose contained in the requested foods.Ninety-three companies (59.6%) responded to the request but did not report the amounts.Of these, 61 (65.6%) replied that such information is a secret formulation and cannot be provided due to internal policy, and 32 (34.4%) re-ported that they could not make this information available, since they do not perform the analysis of sugars separately as the declaration on the food label is not mandatory, and 49 companies (31.4%) did not respond to the request.

Discussion
The main contribution of the study was to show the low availability of information on the amount of lactose in processed foods, either on labels or through the Customer Service Depart-Chart 1. Description of food by food category.

Oils and fats
Margarine; and butter and margarine-derived foods.

Edible iced products
Ice cream and powders for ice cream preparation.
Candy, confectionery, bonbons, chocolates and the like Confectionery (almonds, cashew nuts, chips, sticks, among others); bonbons (with milk chocolate, stuffed with coconut, chocolate with peanuts, and others); hazelnut creams (hazelnut with cocoa, chocolate and hazelnut with wafer); condensed milk; toppings; nougats; chocolates (white, half bitter, aerated with milk, milk, among others); and candies (caramel of milk with cappuccino, caramel of milk stuffed with coconut, among others).

Cereals and cereal or cereal-based products
Cereal bars; morning cereals; milk flours and pasta.

Bakery products and biscuits
Toast; cheese breads; cookies; breads; cakes; bagels; corn-bread; mixes for the preparation of bakery products; pies; cookies and crackers.

Meat and meat products
Sausages; breaded chicken breast; Spanish sirloin and lamb meat.
Sugar and honey Dietetic sweeteners.Soups and broths Corn cream; mixes for the preparation of soups; polenta and bean soup with pasta.

Sauces and seasonings
Sauces (cheese and tomato with ricotta) and pates (pork, turkey breast and ham).

Protein products yeasts
Dairy drinks; curds; milk creams; cheese creams; cheese products; cheeses; curd cheeses; yogurts; infant formulas; dairy compounds and food with isolated soy protein and milk.

Beverages
Liquors; mixes and powders for the preparation of cappuccino or instant milk and coffeebased beverages.

Snacks
Salty and sweet snacks.

Desserts and powders for desserts
Sweets and mixes for the preparation of desserts such as flans, puddings, mousses, among others.

Processed cookery preparations
Lasagna; shepherd's pies; rice; balls; chicken dumplings; vol-au-vents; purees; sandwiches; baby food; pizzas; pancakes; salted cakes; stroganoffs; pies; among others.Nutrition supplements Food supplements; protein bars; nutritional supplement and powders for the preparation of beverages for weight loss diet and powders for the preparation of enriched drinks.Preparations to add to milk Powdered chocolate drink and powders for the preparation of beverages, for example, milkshakes, among others.
31%) § Total number of evaluated foods; £ Total number and percentage of foods with milk in the first position against the total evaluated foods; ǂ Total number and percentage of foods with milk in the second position against the total evaluated foods.ment (SAC).Only 3.0% of the processed foods analyzed showed lactose content on the nutritional table of their label, and only 9.0% of the industries contacted provided such information.Traditional foods had a lower percentage of declaration of lactose content in nutritional tables when compared to diet/light/zero foods.
It is worth mentioning that most of the diet/ light/zero foods that reported the amount of lactose were foods with controlled intake of sugar, lactose-free or lactose-restricted.These data indeed show the compliance by the industries with the specific legislation, such as Ordinance Nº 29/1998 20 and RDC Nº 54/2012 25 , which provide, respectively, foods with controlled intake of sugars and those with complementary nutritional information concerning sugars, which in turn, require the declaration of the amount of sugars in the nutritional information table when a Supplementary Nutrition Information is performed.However, not all diet/light/zero foods contained a declaration of the amount of lactose.
The lack of access to information on the amount of lactose in the label of processed foods violates consumers' fundamental right to information, which consequently impairs their autonomy through the nutritional orientation received and freedom of choice concerning the food consumption 16 .On the other hand, it hinders the nutritionist's work in the calculation and advice on lactose controlled amounts to ensure tolerance, since some people tolerate around 11g (corresponding to 240 ml of milk per day), while others evidence intolerance symptoms 12 with the ingestion of small amounts (2 to 3 g of lactose, corresponding to a small chocolate tablet).The appearance of symptoms depends on the amount of lactose ingested, the type of food in which the lactose was consumed and the degree of lactase deficiency 27 .
Lack of knowledge of the amount of lactose in food may trigger symptoms in the individual, and is a source of distress for the family (especially for mothers of children with this clinical condition) 28 .Therefore, this theme transcends the nutritionist professional practice core and includes a broader field, in which health professionals will have to address the physical and emotional care of the individual and the family, and promote health education, acting in a complementary way 29 .
Other diseases whose fundamental part of the treatment is the total exclusion of some nutrients to avoid the emergence of symptoms and more severe health consequences, such as phe-nylketonuria and celiac disease, already have specific regulations for the declaration of presence on the label, which in these specific cases are for phenylalanine and gluten, respectively [30][31][32][33][34] .However, there are still gaps in the legislation to regulate nutritional labeling for the declaration of essential nutrients for the dietary treatment of some diseases, such as galactosemia and fructose intolerance, inborn metabolism errors that imply the restriction of the substrate (galactose and fructose, respectively) for disease control 35 .
Concerning lactose, Law Nº 13.305 of July 4, 2016 was recently approved and mandates the declaration of the presence of lactose on the labels of food containing lactose and the remaining lactose content in foods whose original lactose content has changed 36 .However, it does not require the declaration of the amount of lactose in foods that have not undergone any change, essential information for patients with lactose intolerance, since lactose must not necessarily be excluded but restricted according to tolerance.
Currently, RDC Nº 26/2015 37 was approved and establishes the requirements for mandatory labeling of the main foods that cause food allergies, including milk, and will also assist individuals with lactose intolerance in the choice of food, but will still not provide the amount of lactose for the appropriate adjustment to individual tolerance.It is worth mentioning that allergy to milk protein and lactose intolerance are different clinical situations.In the former, the individual evidences an immunological response to the presence of milk protein (caseins and whey proteins), whereas poor digestion of milk carbohydrate, namely, lactose 16 , is found in lactose intolerance.
Another critical factor is that even foods that are recommended and more tolerated by patients with lactose intolerance, such as yogurts, may evidence varying amounts (2.1 to 6.4 g of lactose per 100g of yogurt) depending on their form (liquid, flavored or with pieces) 38 , which can cause symptoms in those who consume them.It is worth mentioning that yogurts are recommended because they theoretically have low lactose concentration, because of their hydrolysis in the fermentation process due to the participation of microorganisms, which reduces the amount of lactose in the final product 39 .Some industrial food processing may require the addition of milk or lactose because of its influence on the viscosity, texture and role played by proteins that contribute to softness, lower humidity and higher shelf life of foods 40,41 .
Besides, lactose has a low sweetening power when compared to sucrose.However, its hydrolysis is an alternative for the acquisition of a sweeter syrup containing glucose and galactose, which is a useful process to the food industry, since it allows the production of fermented products (yogurt), it facilitates its use in the formulation of foods without harming the natural flavor of other components and provides technological advantages insofar as it reduces crystallization risks in dairy products and increases sweetening power [42][43][44] .Another useful and promising feature for the industry, especially in the case of infant formulas, is that lactose can promote the absorption of calcium and phosphorus 44 .
As the food industry widely uses them due to the properties mentioned above, these foods can be consumed by people with lactose intolerance, without being aware of the presence and quantity of milk or lactose, which can lead to the appearance of symptoms, since this information is currently not stated on food labels.Thus, it is necessary to alert consumers, especially the lactose intolerant, concerning the consumption of these products.
This study filled a gap in the discussion on lactose labeling in processed foods, as no previous scientific studies were found to verify the availability of information to consumers, es-pecially those with lactose intolerance, on the amount of food lactose.
However, it has been considered that the declaration of milk or lactose in the list of ingredients necessarily implies the presence of lactose in the final product, which is a limitation, since the processing of milk and dairy products and the animal race influence nutritional composition, and especially lactose concentration 45,46 .

Conclusion
There is low availability of information on the amount of lactose in processed foods.This was evidenced in this study by the low percentage of traditional and diet/light/zero foods that directly inform the amount of lactose in food labels and the high proportion of companies that do not provide such data when required.
Thus, it becomes indispensable to standardize and supervise the nutritional labeling of lactose effectively for the general population and, in particular, for individuals with lactose intolerance.The lack of information violates consumers' right to information and can compromise the food and nutritional security of those requiring lactose intake control, as well as impairs the independent choice of food and hampers professional nutritional counseling.

Collaborations
RAB Batista performed the bibliographic review, data collection and analysis, interpretation of the results and drafting of the paper.DCB Assunção participated in data collection, and critically reviewed and approved the final version of the paper.FRO Penaforte performed data statistical analysis, and critically reviewed and approved the final version of the paper.CC Japur idealized and guided the writing and development of the paper (conception, design, analysis and interpretation of data), critically reviewed the writing and approved the final version of the paper.

Table 1 .
Percentage of processed foods containing the declaration of the amount of lactose in the nutritional table of traditional and diet/light / zero food labels.
* P-value < 0.0001; ** P-value <0.05; § Total evaluated: total number of traditional processed and diet / light / zero foods evaluated in this study; £ Total declared: total number of traditional processed and diet / light / zero foods declaring the amount of lactose in the nutritional table of food labels.

Table 2 .
Processed foods with milk in the first or second positions.