What happens to a mother’s milk if she lacks certain nutrients in her diet?

Introduction

Under nutrition and poor health from preventable causes disproportionately affect the well-being of millions of people in the developing world. Factors at individual, household and community level, or a combination of these factors, may contribute to poor nutrition and health status []. In particular, malnutrition among women is likely to have a major impact on their own health as well as their children’s health. More than 3.5 million women and children under age five in developing countries die each year due to the underlying cause of under nutrition [].

Women are more likely to suffer from nutritional deficiency than men for several reasons, including their reproductive biology, low social status, poverty and lack of education. In addition, socio-cultural traditions and disparities in household work patterns can also increase women’s chance of being malnourished []. Between 5 to 20 percent of women in various African countries are underweight. Many African women display low weight-for-height as measured by a body mass index of less than 18.5 [].

Women in low-income settings often consume inadequate amount of micronutrients because of resource limitation. They have a limited intake of animal source foods, fruits and vegetables. Intake of micronutrients less than the recommended values increase women’s risk of micronutrient deficiencies []. Adequate nutritional status of women is important for good health and increased work capacity of women themselves as well as for the health of their offspring [].

Severely malnourished mothers have reduced lactation performance contributing to the increased risk of child mortality [].

Nutritional requirements during lactation are greater than during pregnancy. If a mother is well nourished during pregnancy, she will have adequate fat and other nutrient reserves that can be used to compensate partially for her additional requirements. Mothers should be counseled about the need for an adequate diet in order to achieve optimal lactation and sustain it without depleting their own nutrient stores. Particular attention should be given to intakes of protein, calcium and vitamins [].

Lactating mothers from low-income settings are considered as nutritionally vulnerable group. Due to the nursing process mothers are subjected to nutritional stresses. Frequent pregnancies followed by lactation increase the health risk of mothers resulting in a high maternal mortality []. A nursing mother produces 0.7 to 0.8 liters of milk per day, containing 330 milligrams of calcium per liter. This requires an extra energy expenditure of at least 500 calories per day []. The quality of breast milk is only affected in extreme cases of deprivation, or by excessive intake of a particular food []. But the quantity of milk depends very much on the mother's diet. Food absorbed by a nursing mother not only fulfills her own nutritional needs, which are greater during the postnatal period, but also enables her to produce milk [].

Research based information regarding maternal nutrition from the study communities is lacking. Information on the feeding practices, nutritional status and associated factors of the lactating women are urgently needed for prioritizing, designing and initiating intervention programs aimed at improving maternal nutrition. The process for priority setting should start with the assessment and analysis of the situation that lactating women face in their environment. Thus, this study was carried out to provide information regarding the feeding practices, nutritional status and associated factors of the lactating women in the study area.

Methods and materials

Study area and population

The study was conducted in 2 rural and 2 urban kebeles [Kebele is the lowest administrative unit in Ethiopia consisting of about 1200 households] of Samre Woreda from March-April, 2011. The study area has a total population of 137,423 of which 70,086 [51%] were male, and 67,337 [49%] were female. Among these, 5222 [3.8%] were lactating mothers []. The study area is characterized by household food insecurity []. The total number of kebeles and schools were 23 and 48, respectively. The potential health service coverage in the study area was 85% []. The major agricultural products are wheat, barley, teff, sorghum, pea and beans and some vegetables like cabbage, carrots and lettuce [].

Study design and sampling

The study used a community-based cross-sectional survey design and data were collected from lactating mothers between the ages of 15-49 years. A sample size of 400 lactating mothers was calculated using a single population proportion formula with a 95% confidence level, 5% margin of error, 38% estimated prevalence of chronic energy deficiency in the study area [], and by considering a non-response rate of 10%. The total kebeles in the woreda were initially stratified into rural and urban areas. Then, four [two from each strata] were selected from the existing 23 kebeles [4 urban & 19 rural] based on Probability Proportional to Size [PPS] sampling technique. The households in the selected kebeles with lactating mothers were identified through house-to-house visits by the research assistants. A sampling frame was prepared by registering all the identified eligible lactating women in each kebele. After that, simple random sampling was used to select the required number of lactating mothers.

Data collection

Socio-demographic information

Trained female research assistants fluent in the local language [Tigrigna] administered the pre-tested questionnaire to selected lactating mothers in their own respective homes. The questionnaire was used to assess the socio-demographic characteristics, maternal characteristics, and the feeding patterns of the lactating mothers. Data on frequency of foods eaten and dietary diversity was also assessed using the questionnaire. Dietary diversity score [DDS] was collected and calculated as the sum of the number of different food groups consumed by the mother in the 24 hours prior to the assessment. A total of 14 food groups were considered in this study [i.e. cereals, vitamin A rich vegetables and tubers, white tubers and roots, dark green leafy vegetables, other vegetables, vitamin A rich fruits, any meat, egg, fish, legumes and nuts, milk and milk products, oils and fats, condiments and beverages, sweets] [].

Dietary intake assessment

A one-day [24 hr] weighed food record was collected from randomly selected sub sample of study participants [n=60]. The dietary assessment period lasted from the time the mother ate her breakfast to the time of dinner. For this reason, the trained female research assistants [four in each kebele] stayed in the study households from early morning until the mother’s last meal and weighed portions of the food consumed by the mother and any left over at the completion of each meal to deduct from the weight of the original serving. Foods and beverages consumed by the mother were weighed using digital scales [2 kg maximum weight: Model CS 2000, Ohaus Corporation, USA] accurate to±1 g. While weighing the foods and drinks, a detailed description of the foods and their cooking methods were recorded. To account for any day of the week effects on food and/or nutrient intake, weekends, weekdays and market days were proportionately represented in the survey. Study participants were well informed not to change their normal dietary pattern over the food record day. They were also asked to eat separately and not to share their meals during the day of data collection.

Anthropometric measurements

Weights of the lactating women were measured to the nearest 0.1 kg on a battery powered digital scale [Seca 770, Hanover Germany] and heights were measured to the nearest 0.1 cm using a wooden height-measuring board with a sliding head bar following standard anthropometric techniques []. Mid upper arm circumference [MUAC] was also measured using a non-stretchable MUAC tape []. For weight and height measurements, study subjects removed their shoes, removed their jackets and wore light clothing. Triplicate measurements of weight, height, and mid upper arm circumference were taken at the same day from each study subject using calibrated equipments and standardized techniques []. To avoid variability among the data collectors, all the anthropometric measurements were taken by the researcher [principal investigator]. Body mass index [BMI] of the study subjects was calculated by dividing the weight in kilogram to the height in meter squared [kg/m2].

Data analysis

The nutrient and energy content of foods consumed by the mothers was calculated by using ESHA Food Processor and the Ethiopian Food Composition Tables [, ]. Statistical analysis was carried out using SPSS for windows version 17.0 [SPSS Inc.]. Continuous variables were checked for normality using the Kolmogorov-Smirnove test, scatter plots and histograms. Descriptive summaries using frequencies and proportions were used to present the study results. To investigate the socio-economic and demographic factors affecting the nutritional status of the women, logistic regression was used. Significant variables observed in the bivariate analysis were subsequently included in to the multivariate analysis. ANOVA and t-test were also used to see if there was a mean difference in nutritional status among the lactating mothers. P-values less than 0.05 were considered as significant.

Ethical considerations

The study protocol was reviewed and approved by the Institutional Review Board of the College of Health Sciences at Hawassa University. Permission to undertake the study was obtained from every relevant authority in the woreda. The nature of the study was fully explained to the study participants to obtain their oral informed consent prior to participation in the study and data was kept confidential. No resistance was made if a woman wanted to withdraw at any time from participating in the research.

Operational definitions

Dietary Intake: the amount of energy, nutrients or anti-nutrients available in the food consumed by the lactating mothers.

Dietary Practice: eating habit of the mothers during the time of their lactation.

Lactating Mother: mother who is currently feeding breast milk for her infant/child.

Individual Diet Diversity Score: is the sum of food groups eaten in a specified reference period, serves as a proxy of nutrient adequacy of an individual’s diet.

Permanent Residents: women who live in the study area for more than six months.

Portion Size: the amount of a food item consumed at a time.

Women in the reproductive age: relates to the standard recommendation of 15-49 years.

Recommended Nutrient Intake: also referred to as the Reference Daily Intake, is a term generally used to describe nutrient intake in regards to the majority of healthy people in a particular stage of life and of a particular gender.

Results

Socio-demographic characteristics of the study participants

A total of 400 lactating mothers aged 15-49 years were interviewed, with a response rate of 100%. The study participants included 200 lactating mothers from rural areas [kebeles] and 200 lactating mothers from urban areas. More than two thirds of the study participants, 275 [68.3%], were in the age range of less than or equal to 30 years and all of them [100%] belong to the Tigray ethnic group. Majority, 353 [88.25%] of the study participants lived in male-headed households. More than three fourths, 307 [77.3%] of the mothers in this study were housewives, whereas, only 93 [21.7%] were involved in income generating activities [Table ].

Table 1 Socio-demographic characteristics of the study participants [n=400] in Samre Woreda from March-April, 2011

Full size table

Maternal health and feeding practices

Majority of the study participants, [92%] received ante natal care [ANC] at least once during their last pregnancy, but only 45.5% had ANC visits of greater than or equal to 4 times [which is recommended]. Slightly above half, [54.1%] of the study participants had 3-6 previous pregnancies. Almost all, 397 [99.3%] of the study subjects did not avoid any food because of cultural/traditional reasons, whereas, only 115 [28.8%] of them were eating additional foods during their lactation period [Table ].

Table 2 Maternal health and feeding practices of the study participants [n=400] in Samre Woreda from March-April, 2011

Full size table

Anthropometric status of the study participants

The mean height [±SD], weight [±SD], MUAC [±SD] and BMI [±SD] of the study participants were 156.0 cm [±5.4], 48.3 kg [±5.7], 23.2 cm [±1.9] and 19.8 kg/m2[±2.0], respectively. One hundred [25%] of the study participants had a BMI less than 18.5 kg/m2 [chronically energy deficient]; whereas only 7 study participants had a BMI greater than or equal to 25 kg/m2 [over weight]. Study subjects with a height of less than or equal to 145 cm [stunted] and with a weight of less than or equal to 45 kg [underweight] were 9 [2.2%] and 124 [31%], respectively [Table ].

Table 3 Anthropometric status of the study participants [n=400] in Samre Woreda from March-April, 2011

Full size table

Dietary intakes of the study participants

Majority of the study participants 369 [99.3%] consumed cereal based foods [made of teff, wheat, sorghum, millet, and barley]. About three fourths 297 [74.3%] of the study participants reported that they consumed legumes prior to the survey and more than three fourths 366 [91.5%] of the study subjects consumed foods cooked with oil, fat or butter in the previous 24 hours. Other vegetables [tomato, onion] and dark green vegetables [kale and green pepper] were consumed by 347 [86.8%] and 158 [39.5%] of the study participants, respectively.

Other white vegetables and tubers [white potato, white sweet potato] and vitamin A rich vegetables [pumpkin, carrot] were consumed by 130 [32.5%] and 102 [25.5%] of the study subjects, respectively. Ninety four [23.5%] of the study participants reported that they consumed other fruits [banana, lemon and orange] where as fifty one [12.8%] reported that they consumed vitamin A rich fruits [ripe mango and papaya], a day prior to the survey. Among animal products, milk and milk products were consumed by 22 [5.5%] of the study subjects where as egg, flesh meat and organ meat were consumed by 20 [5%], 15 [3.8%] and 9 [2.3%], respectively.

Comparison of the median energy and other selected nutrients intake of the women

Except iron [118 mg], which is by far higher than the recommended nutrient intake [10 mg], other median nutrient intakes as well as energy intakes of the lactating women in the study area were less than the recommended nutrient intakes of FAO/WHO/ UNU []. Vitamin C [23 mg] and vitamin A [194 micro grams] were considerably lower than the recommended nutrient intakes of the lactating women. The phytate content of the diet consumed by the lactating mothers in the study area was extremely high [1872 mg] [Table ].

Table 4 Median [25 th and 75 th percentile] energy and nutrient intakes of the lactating women in comparison with the EER and recommended nutrient intakes, [n=60]

Full size table

Socio-economic and demographic factors associated with the nutritional status [MUAC] of the lactating mothers

Size of farmland had a significant association on the nutritional status [MUAC] of the lactating mothers, i.e. those who had a land size of 0.26-0.75 hectare were 5.1 times more likely to be malnourished [MUAC < 21 cm] than those who had a land size of greater than 0.75 hectare [AOR=5.1,95% CI [1.06,24.46]]. Those whose years of marriage was between 11-20 years were 71% less likely to be malnourished [MUAC < 21 cm] than those whose years of marriage was less than or equal to 10 years [AOR=0.29, 95% CI [0.09, 0.9]]. Similarly, those who were not growing maize were 3 times more likely to be malnourished [MUAC < 21 cm] than those who were growing it [AOR=3, 95% CI [1.3, 7.2]].

But, nutritional status as determined by MUAC did not reveal any statistical association with family size, farm animal ownership, maternal educational status, number of meals per day, age of breast feeding child, number of parity and eating additional food during lactation [Table ].

Table 5 Association of some socio-demographic variables with the nutritional status [MUAC] of the study participants [n=400] in Samre Woreda from March-April, 2011

Full size table

Socio-economic and demographic factors associated with the nutritional status [BMI] of the lactating mothers

Frequency of ANC visit had a significant association with the nutritional status [BMI] of the lactating mothers, i.e., women who had ANC visits of less than or equal to 3 times were 2.9 times more likely to be malnourished [BMI < 18.5 kg/m2] than those who had more than 3 ANC visits [AOR=2.9, [1.2, 7]]. Similarly, women who had children aged greater than 12 months were 2.8 times more likely to be malnourished [BMI < 18.5 kg/m2] than those who had children aged less than or equal to 12 months [AOR=2.8, [1.4, 5.8]].

But, nutritional status of study participants according to BMI classification had no significant association with maternal educational status, household asset [radio] ownership, family size, maternal age, number of meals per day, number of parity, farm animal ownership and residence [Table ].

Table 6 Association of some socio-demographic variables with the nutritional status [BMI] of the study participants [n=400] in Samre Woreda from March-April, 2011

Full size table

Discussion

This study assessed the feeding practices, nutritional status and associated factors among lactating women from Samre woreda, South Eastern Zone of Tigray, Ethiopia. According to the essential nutrition action [ENA], taking at least two additional meals per day during lactation is recommended for all lactating women []. Nevertheless, slightly below three fourth’s 285 [71.3%] of the study participants do not take any additional meal during their lactation time. The median dietary diversity score of the study participants was 5.0, which was lower than half of the food groups on FAO food grouping i.e. 14 food groups [].

The prevalence of chronic energy deficiency [BMI