The Prevalence Of Lactose Intolerance In Three Generations And Dietary Measurements To Ameliorate Its Symptoms

Lactose intolerance (LI)exists in the subjects with lactase deficiency(LD),which have gastrointestinal symptoms including abdominal distension,cramps,flatulence,and watery stools after consuming lactose and its foods. For this reason, milk and dairy products are eliminated from the diet of many LI subjects, which could lead to the nutrition-related diseases, especially disease related to calcium-deficiency,such as rickets, osteoporosis and asteomalacia etc. In China, the prevalence of LI is 65.5-67% in adults and 28.2-32% in children. Therefore, increasing calcium intake via ameliorating LI symptoms is one of important issue in nutrition.Despite the results from a lot of epidemiological studies indicate LI maybe relate with long-term non-milk drinking, but whether is the decline of lactase activity in adult of Chinese caused by less milk drinking or non-milk drinking habit is not clear yet. Results from our research group suggested that subjects with LI had low lactase activity but still had residual lactase activity that can absorb some amount of lactose. Can LI subjects drink milk? How much milk could they accept? These questions should be answered. Studies by our research group also demonstrations that the serious symptoms after milk ingestion in LI subjects may vary widely, depending upon not only the degree of intestinal lactase deficit but also gastric emptying time ,orocecal transit time and colonic micro flora in subjects. It is a good way to increasing intake of cow's milk in LI subjects by exploring various foods and milk drinking manner to delaying gastric emptying.The aim in present study is to investigate milk consumption in three generations, including children, their parents and grandparents, and to analyze the effects of drinking cow's milk on prevalence of LI based on many studies including our program. The acceptable intake of cow's milk for healthy adults and measures of alleviating symptoms of LI were put forward in the present study. When people drank the milk, combining eating habits of our residents by epidemiology survey and human trail. Therefore the results of the present study will play an important role in the practice in pushing civil milk drinking program, improving calcium level of Chinese people.The present study includes three parts as follows:1. Study on prevalence and influencing factors of lactose intolerance in three generations include children, parents and grandparentsObjective: To investigate milk consumption and effect on health of three generations include children, parents and grandparents, and to analyze the prevalence and influencing factors of LI among them, and to explore the effect of long-term and generations's milk drinking behavior to lactase. Methods: 55 children aged 3-6 include their parents and grandparents 358, which selected from 3 three kindergartens in Chengdu and its suburb by clustered random sampling, were investigated by questionnaire, accumulative Cow's Milk Intake per year(AMIy) by frequencies,years,amounts of milk that they drank in their lifetime..LI were diagnosed by Hydrogen Breath Test (HBT) and stool lactose (by the way of lead acetate with aqueous ammonia) in 243 persons among those three generations. Statistical analysis is carried out by SPSS11.0.Results 1.The rate of milk drinking in children, parents and grandparents was 74.6%,48.1% and 32.0% respectively; 66.1% of parents and grandparents take a dislike to milk and are unaccustomed to it .The height and weight of children with milk drinking habit were more higher and heavier than those with non-milk drinking habit(P＜0.05, respectively) .There were positive correlations between AMIy of children and their height,weight (r is 0.353,0.380 ,P=0.000 ,respectively) .The rate of milk drinking and AMIy in adults with leg cramp and waist ache were significant in comparing with that of those with non-symptoms (P＜0.005,P=0.000,respectively) .There were positive correlations between AMIy of children and that of mother, grandparents (r is 0.614,0.447, P＜0.01 respectively) .There were correlation between AMIy of adults and their cultural standard. AMIy of person graduated from senior high school and college is significant in comparing with that of which graduated from junior high school or below (P＜0.05) .2. Concordance of diagnose LD by HBT and the way of lead acetate with aqueous ammonia: Kappa value was 0.421 (P＜0.01) ,sensitivity was 83.3%, specificity was 60.7%.3. The prevalence of LI in children ,parents and grandparents was 50.9%,68.8%,67.6% respectively. The prevalence of LI in adults those with un-milk drinking habit was significant in comparing with those with milk drinking per day (x~2=21.452 P＜0.05). The prevalence of LI in child whose parents and grandparents with un-milk drinking habit was significant in comparing with those milk drinking habit (x~2=4.57 P＜0.01) .4.There were negative correlations between AMIy and severity degree of LI symptom (r=-0.353, P＜0.05)。Binary Logistic regression showed that: years, frequency, and amount of milk per time that they drank in their lifetime were with statistical significance (P＜0.05) There were negative correlations between years , frequency of milk drinking and LI ,OR were 0.317,0.465, respectively. There were positive correlations between amount milk of per time and LI, OR was 6.337Conclusion: 1.The rate of milk drinking in children, parents and grandparents was 74.6%,48.1% and 32.0% respectively. Drinking milk can improve children's growth and development. Leg cramp and waist ache of adults are related with accumulative Cow's Milk Intake per year (AMIy).Children's milk drinking habits were significantly influenced by mother. Cultural standard of adults can affect their milk drinking habits2. LI is related to milk drinking. There were negative correlations between years , frequency of milk drinking and LI symptoms. There were positive correlations between amount of milk per time and LI symptoms.Drinking moderate amount milk for years per day might alleviate the symptoms of intolerance3. LI of the child is related to un-milk drinking of his parents and grandparents.4. A MIy is preferable index to rough estimate milk intake.5. stool lactose eaxamined by the way of lead acetate with aqueous can be used for screening LD.2. Study on the acceptable intake of cow's milk for severe LI Objective: To find out the acceptable intake of cow's milk in subjects with severe LI and then observe intolerance symptoms in healthy adults after they drank thus allowance.Methods: Eight LI subjects with watery diarrhea who were selected from 38 subjects by HBT were divided into group A, group B to go on drinking cow's milk test. The subjects in group A ingested 25g milk powder, the subjects in group B ingested 38.2g milk powder(contain 6.25g,9.55g lactose and make 200 ml of milk solution respectively) according to literature and single factor optimization method(0.618 golden mean) to analyze their△hydrogen excretion(mg/m~3) ,symptom score and stool lactose. The 100 younger, the 80 middle-age and the 100 elder subjects were selected by clustered random sampling to observe symptoms after they ingested 25g milk powder.Results: No case with diarrhea occurred in these two group but mild symptoms (burp, break wind). hydrogen excretion(mg/m~3) and symptom score in the high dose group (group B)are a little higher than those in low dose group (group A) . Most of healthy adults (80.3%) have no intolerance symptoms after they ingested 25g milk powder (make 200 ml of milk solution).Conclusion: There was only mild symptoms after LI with diarrhea ingested 25g cow's milk powder ,no bellyache ,loose and water stool occurre.The study demonstrates that most of adults, even with LI, can tolerance 25g cow's milk powder(6.25g lactose). According to the condition of our country. It is suggested 20g cow's milk powder(5g lactose, make 160 ml of milk solution) is the acceptable intake of healthy adults in China.3. Study on measures of ameliorating symptoms of LI during drinking milkObjective: To find out measurements of alleviating symptoms of LI when people drank the milk, combining diet habits of our residents.Methods: Eight LI subjects with watery diarrhea who were selected from 38 subjects by HBT were divided into 4 groups to go on drinking cow's milk test with various foods by orthogonal trail. The 100 healthy college students were selected by clustered random sampling to observe symptoms after they ingested 25g milk powder by different manners.Results:△hydrogen excretion of groups which ingested milk with various food is lower than those ingested milk only(all less than 1.786 mg/m~3). Egg is better than Manitou in alleviating symptoms. (F value of stool lactose and symptom score are 7.5,9.0 ,respectively＜0.05) .Whole wheat bread can aggravate flatus. The prevalence of the symptom in 100 college students by drinking milk in fast state (27/98) was significantly comparing with that by drinking milk with regular meal (13/98), (x~2=6.16, P＜0.05) .Conclusion: The study demonstrates that various foods, various milk drinking manner can affect the intolerance symptom .We suggested:Don't drink milk in fast state, milk with egg and staple food such as steamed bread, bread or gomuti is best selection for breakfast. Drinking milk with regular manner can alleviate symptom of intolerance. For lactose intolerance, don't take whole wheat bread. In general, LI of the child is related to un-milk drinking of his parents and grandparents .It is provided powerful evidence to demonstrate that lactase gene polymorphism (lactase persistence and nonpersistence)is related with long-term drinking and non drinking milk.LI subject should release from incapable of drinking milk .It is not only alleviating symptoms of LI but also improving intake of cow's milk when LI subjects keep on drinking milk or eat other dairy products which contain less 5g lactose per time for long term.