Cow's milk and linear growth in industrialized and developing countries

Dietary predictors of the insulin-like growth factor system in adolescent females: results from the Dietary Intervention Study in Children (DISC)

BACKGROUND

The insulin-like growth factor (IGF) system is associated with the adult diet and chronic disease. Childhood diet may influence chronic disease through its effect on the IGF system; however, there is limited information describing the dietary predictors of the IGF system in adolescents.

OBJECTIVE

We examined associations between dietary food intake [fat, protein (animal and vegetable), carbohydrate, lactose, dietary fiber, calcium, zinc, and sodium] and serum IGF-I, IGF binding protein 1 (IGFBP-1), IGF binding protein 3 (IGFBP-3), and the IGF-I:IGFBP-3 molar ratio in adolescent females.

DESIGN

One hundred fifty-nine adolescent females in the Dietary Intervention Study in Children (age range: 14-18 y; 0.2-6.3 y postmenarche) were included. The dietary intake was assessed via three 24-h dietary recalls. IGF-related biomarkers were determined by using radioimmunoassays. Associations between dietary intakes and biomarkers were assessed with Pearson's correlations and multivariable linear regression. Dietary intakes and biomarkers were logarithmically transformed; thus, beta coefficients represented percentages.

RESULTS

In analyses adjusted for energy, age, and time since menarche, significant correlations (P < 0.05) were as follows: IGF-I with total protein, lactose, calcium, and sodium; IGFBP-3 with total fat (inverse), lactose, fiber, and calcium; IGF-I/IGFBP-3 with lactose and calcium; and IGFBP-1 with vegetable protein. In multivariable analyses, significant predictors of IGF-I were energy (beta = 0.14, P < 0.05) and calcium (beta = 0.14, P < 0.01), the significant predictor of IGFBP-3 was calcium (beta = 0.07, P < 0.05), and significant predictors of IGFBP-1 were vegetable protein (beta = 0.49, P < 0.05) and body mass index-for-age percentile (beta = -0.01, P < 0.001).

CONCLUSION

This study provides evidence that dietary intake affects IGF-related biomarkers-particularly elevated calcium with IGF-I and IGFBP-3 and elevated vegetable protein with IGFBP-1-and, to our knowledge, is novel in reporting these associations in adolescent females. The Dietary Intervention Study in Children was registered at clinicaltrials.gov as NCT00000459.

Cash and in-kind transfers in poor rural communities in Mexico increase household fruit, vegetable, and micronutrient consumption but also lead to excess energy consumption

Conditional transfer programs are increasingly popular, but the impact on household nutrient consumption has not been studied. We evaluated the impact of the Programa de Apoyo Alimentario (PAL), a cash and in-kind transfer program, on the energy and nutrient consumption of poor rural households in Mexico. The program has been shown to reduce poverty. Beneficiary households received either a food basket (including micronutrient-fortified milk) or cash. A random sample of 206 rural communities in Southern Mexico was randomly assigned to 1 of 4 groups: a monthly food basket with or without health and nutrition education, a cash transfer with a cost to the government equivalent to the food basket (14 USD/mo) with education, or control. The impact after 14 mo of exposure was estimated in a panel of 5823 households using a double difference regression model with household fixed effects. PAL was associated with increases (P < 0.01) in the consumption of total energy (5-9%), energy from fruits and vegetables (24-28%), and energy from animal source foods (24-39%). It also affected iron, zinc, and vitamin A and C consumption (P < 0.05). The consumption of energy and all nutrients was greater in the food basket group (P < 0.05). Cash and in-kind transfers in populations that are not energy-deficient should be carefully redesigned to ensure that pulling poor families out of poverty leads to improved micronutrient intake but not to increased energy consumption.

Choice of foods and ingredients for moderately malnourished children 6 months to 5 years of age

There is consensus on how to treat severe malnutrition, but there is no agreement on the most cost-effective way to treat infants and young children with moderate malnutrition who consume cereal-dominated diets. The aim of this review is to give an overview of the nutritional qualities of relevant foods and ingredients in relation to the nutritional needs of children with moderate malnutrition and to identify research needs. The following general aspects are covered: energy density, macronutrient content and quality, minerals and vitamins, bioactive substances, antinutritional factors, and food processing. The nutritional values of the main food groups--cereals, legumes, pulses, roots, vegetables, fruits, and animal foods--are discussed. The special beneficial qualities of animal-source foods, which contain high levels of minerals important for growth, high-quality protein, and no antinutrients or fibers, are emphasized. In cereal-dominated diets, the plant foods should be processed to reduce the contents of antinutrients and fibers. Provision of a high fat content to increase energy density is emphasized; however, the content of micronutrients should also be increased to maintain nutrient density. The source of fat should be selected to supply optimal amounts of polyunsaturated fatty acids (PUFAs), especially n-3 fatty acids. Among multiple research needs, the following are highlighted: to identify the minimum quantity of animal foods needed to support acceptable child growth and development, to examine the nutritional gains of reducing contents of antinutrients and fibers in cereal- and legume-based diets, and to examine the role of fat quality, especially PUFA content and ratios, in children with moderate malnutrition.

Poor dietary quality of complementary foods is associated with multiple micronutrient deficiencies during early childhood in Mongolia

Objective

To assess whether persistent micronutrient deficiencies in Mongolian children identified in our earlier biochemical study are associated with inadequacies in quantity and/or quality in their complementary diets.

Design

A cross-sectional study of breast-fed children aged 6–23 months, randomly selected from four districts in Ulaanbaatar and four provincial capitals.

Subjects

Weight and length were measured, and sociodemographic status, feeding practices and nutrient adequacy of complementary foods for children aged 6–8 months (n 26), 9–11 months (n 29) and 12–23 months (n 73) were assessed via questionnaire and in-home interactive 24 h recalls.

Results

No geographic differences existed so data were combined. Adherence to WHO infant and young child feeding practices was poor: few children were exclusively breast-fed up to 6 months of age or received the recommended number of feedings containing the recommended number of food groups. Nevertheless, energy intakes from complementary diets, primarily from cereals and non-nutritious snacks, were above WHO-estimated needs; <1 % of energy was from meat and eggs or fruits and vegetables. Median intakes and densities of most nutrients (except protein, thiamin and riboflavin) failed to meet WHO recommendations for at least two age groups, assuming average breast milk intake; greatest density deficits were for Fe > vitamin C > vitamin A > Zn > Ca.

Conclusions

Complementary feeding in Mongolia is compromised by deficits in several micronutrients but not energy, in part because of frequent consumption of non-nutritious snacks. The latter may interfere with breast-feeding and should be avoided. Instead, wheat-based complementary foods should be enriched with affordable cellular animal foods and fruits rich in vitamin C to combat existing micronutrient deficits.

Current and Potential Role of Specially Formulated Foods and Food Supplements for Preventing Malnutrition among 6- to 23-Month-Old Children and for Treating Moderate Malnutrition among 6- to 59-Month-Old Children

Reducing child malnutrition requires nutritious food, breastfeeding, improved hygiene, health services, and (prenatal) care. Poverty and food insecurity seriously constrain the accessibility of nutritious diets that have high protein quality, adequate micronutrient content and bioavailability, macrominerals and essential fatty acids, low antinutrient content, and high nutrient density. Diets based largely on plant sources with few animal-source and fortified foods do not meet these requirements and need to be improved by processing (dehulling, germinating, fermenting), fortification, and adding animal-source foods, e.g., milk, or other specific nutrients. Options include using specially formulated foods (fortified blended foods, commercial infant cereals, or ready-to-use foods [RUFs; pastes, compressed bars, or biscuits]) or complementary food supplements (micronutrient powders or powdered complementary food supplements containing micronutrients, protein, amino acids, and/or enzymes or lipid-based nutrient supplements (120 to 250 kcal/day), typically containing milk powder, high-quality vegetable oil, peanut paste, sugar, and micronutrients. Most supplementary feeding programs for moderately malnourished children supply fortified blended foods, such as corn–soy blend, with oil and sugar, which have shortcomings, including too many antinutrients, no milk (important for growth), suboptimal micronutrient content, high bulk, and high viscosity. Thus, for feeding young or malnourished children, fortified blended foods need to be improved or replaced. Based on success with ready-to-use therapeutic foods (RUTFs) for treating severe acute malnutrition, modifying these recipes is also considered. Commodities for reducing child malnutrition should be chosen on the basis of nutritional needs, program circumstances, availability of commodities, and likelihood of impact. Data are urgently required to compare the impact of new or modified commodities with that of current fortified blended foods and of RUTF developed for treating severe acute malnutrition.

Differential effects of casein versus whey on fasting plasma levels of insulin, IGF-1 and IGF-1/IGFBP-3: results from a randomized 7-day supplementation study in prepubertal boys

BACKGROUND/OBJECTIVES

Milk increases both fasting insulin and insulin-like growth factor 1 (IGF-1), and thereby growth, in healthy prepubertal boys. It is, however, unknown which components in milk are responsible for milk's growth-stimulating effect.

SUBJECTS/METHODS

To get closer to the identification of which components in milk that stimulate growth, we have performed an intervention study with 57 eight-year-old boys in which we examined the effects of the two major milk protein fractions, whey and casein, and milk minerals (Ca and P) in a 2 x 2 factorial design on IGFs and glucose-insulin metabolism. The amounts of whey and casein were identical to the content in 1.5 l skim milk. The amounts of Ca and P were similar to 1.5 l skim milk in the high-mineral drinks, whereas the amounts of Ca and P were reduced in the low-mineral drinks.

RESULTS

There were no interactions between milk mineral groups (high, low) and milk protein groups (whey, casein). Serum IGF-1 increased by 15% (P<0.0001), whereas there was no change in fasting insulin (P=0.36) in the casein group. In the whey group, fasting insulin increased by 21% (P=0.006), with no change in IGF-1 (P=0.27). There were no independent effects of a high milk mineral intake on IGF-1 and insulin.

CONCLUSIONS

The main milk protein fractions exhibit important but different growth-promoting effects by increasing either fasting insulin (whey) or IGF-1 (casein) levels.

Nutrition and bone growth in pediatrics

Children's growth is a hallmark of their normal development and the association between nutrition and linear growth in children is well accepted. Growth requires an adequate supply of many different nutritional factors, some form the "building materials," whereas others play regulatory roles. In this article we describe the growth of the growth plate and discuss the role of nutritional affected hormones on this process. In addition we describe the effect of local regulators and nutritional factors on the growth process and suggest the involvement of new regulatory factors in the translation of nutrition to growth.

Role of insulin, insulin-like growth factor-1, hyperglycaemic food and milk consumption in the pathogenesis of acne vulgaris

It is the purpose of this viewpoint article to delineate the regulatory network of growth hormone (GH), insulin, and insulin-like growth factor-1 (IGF-1) signalling during puberty, associated hormonal changes in adrenal and gonadal androgen metabolism, and the impact of dietary factors and smoking involved in the pathogenesis of acne. The key regulator IGF-1 rises during puberty by the action of increased GH secretion and correlates well with the clinical course of acne. In acne patients, associations between serum levels of IGF-1, dehydroepiandrosterone sulphate, dihydrotestosterone, acne lesion counts and facial sebum secretion rate have been reported. IGF-1 stimulates 5alpha-reductase, adrenal and gonadal androgen synthesis, androgen receptor signal transduction, sebocyte proliferation and lipogenesis. Milk consumption results in a significant increase in insulin and IGF-1 serum levels comparable with high glycaemic food. Insulin induces hepatic IGF-1 secretion, and both hormones amplify the stimulatory effect of GH on sebocytes and augment mitogenic downstream signalling pathways of insulin receptors, IGF-1 receptor and fibroblast growth factor receptor-2b. Acne is proposed to be an IGF-1-mediated disease, modified by diets and smoking increasing insulin/IGF1-signalling. Metformin treatment, and diets low in milk protein content and glycaemic index reduce increased IGF-1 signalling. Persistent acne in adulthood with high IGF-1 levels may be considered as an indicator for increased risk of cancer, which may require appropriate dietary intervention as well as treatment with insulin-sensitizing agents.

Height, wealth, and health: an overview with new data from three longitudinal studies

This overview, based on a literature review and new data from the three cohorts (Whitehall Studies I and II, and the Vietnam Experience Study), has four objectives: (a) to outline the major determinants of height, so providing an indication as to what exposures this characteristic may capture; (b) to summarise, by reviewing reports from large scale studies, the relation between adult height and a range of disease outcomes--both somatic and psychiatric--with particular emphasis on coronary heart disease (CHD) and stroke; (c) to discuss why these relationships may exist, in particular, the role, if any, of socioeconomic position in explaining the apparent associations; and, finally (d) to outline future research directions in this field. The large majority of evidence for predictors of height, and its health consequences, comes from observational studies. While genetic predisposition is a major determinant of height, secular rises in childhood and adult stature across successive birth cohorts suggest that early life environment also has an important impact. Plausible non-genetic determinants of height include nutrition, illness, socioeconomic status, and psychosocial stress. Evidence for an association between height and a series of health endpoints is accumulating. Thus, shorter people appear to experience increased risk of CHD, and these associations appear to be independent of socioeconomic position and other potentially confounding variables. For stroke, and its sub-types, findings are less clear. In contrast to CHD, some cancers, such as carcinoma of the colorectum, prostate, breast (in women), central nervous system, skin, endometrium, thyroid and blood (haematopoietic) are more common in taller people. While height may be negatively related to the risk of completed suicide, conclusions about the links between stature and other health endpoints is problematic given the paucity of evidence, which should be addressed. Ultimately, for want of better data, investigators in this area have used height as a proxy for a range of pre-adult exposures. In future, research should aim to explore the predictive capacity of direct measures of diet, psychosocial stress, childhood chronic illness and so on, rather than focus on height or its components. The problem is that extended follow-up of child cohorts with such data are required, and studies which hold these data are not currently available, although several are either maturing to the point where they offer sufficient clinical outcomes to facilitate analyses or are in the advanced planning stage.

Insulin-like growth factor I concentrations in infancy predict differential gains in body length and adiposity: the Cambridge Baby Growth Study

BACKGROUND

Formula milk-fed infants show faster rates of growth and weight gain than do breastfed infants, and they have higher concentrations of insulin-like growth factor I (IGF-I).

OBJECTIVE

Our objective was to determine the influence of IGF-I concentrations on gains in weight, length, body mass index (BMI), and adiposity in the first year of life.

DESIGN

IGF-I concentrations were measured in 953 capillary blood samples from 675 unselected infants at ages 3 and 12 mo. These infants were born between 2002 and 2008 in one center and were participating in a prospective longitudinal birth cohort. Weight, length, and 4 skinfold thicknesses as an indicator of adiposity were measured at ages 0, 3, and 12 mo. Analyses were adjusted for age and sex.

RESULTS

Infants who were formula milk-fed had higher IGF-I concentrations at 3 mo, and they showed greater gains in weight, length, BMI, and adiposity between age 3 and 12 mo. IGF-I concentrations at 3 mo were unrelated to subsequent overall weight gain (P = 0.5). However, higher IGF-I concentrations at age 3 mo predicted greater subsequent gains in body length (P < 0.001 and P = 0.007 in formula milk-fed and breastfed infants, respectively) and slower gains in BMI (P < 0.001 and P = 0.004, respectively) and adiposity (P = 0.03 and P = 0.003, respectively).

CONCLUSIONS

Our findings support a key role for IGF-I in the partitioning of overall infant weight gain into statural growth compared with adiposity. In formula milk-fed infants, higher IGF-I concentrations may lead to faster gains in length; however, other mechanisms likely explain their faster gains in weight, BMI, and adiposity.

Androgen abuse in the community

PURPOSE OF REVIEW

To provide information of the current prevalence of illicit use of androgens by individuals of the community.

RECENT FINDINGS

Prevalence of abuse of androgens in individuals of the general population has reached alarming dimensions. Use of androgens is no longer limited to competitive sports, but has spread to leisure and fitness sports, bodybuilding, and nonathletes motivated to increase muscular mass and physical attractiveness. Alarming studies from Germany demonstrated that members of the healthcare systems provide illegal androgens to 48.1% of abusers visiting fitness centers. The new trend to combine androgens with growth hormone, insulin, and insulinotropic milk protein-fortified drinks may potentiate health risks of androgen abuse.

SUMMARY

The use of androgens has changed from being a problem restricted to sports to one of public health concern. The potential health hazards of androgen abuse are underestimated in the medical community, which unfortunately contributes to illegal distribution of androgens. Both the adverse effects of current androgen abuse especially in young men as well as the chronic toxicity from past long-term abuse of now middle-aged men has to be considered as a growing public health problem. In the future, an increasing prevalence of androgen misuse in combination with other growth-promoting hormones and insulinotropic milk protein products has to be expected, which may have further promoting effects on the prevalence of chronic western diseases.

Supplementary feeding with fortified spread among moderately underweight 6-18-month-old rural Malawian children

We aimed to analyse growth and recovery from undernutrition among moderately underweight ambulatory children receiving micronutrient-fortified maize-soy flour (Likuni Phala, LP) or ready-to-use fortified spread (FS) supplementary diet. One hundred and seventy-six 6-18-month-old individuals were randomized to receive 500 g LP or 350 g FS weekly for 12 weeks. Baseline and end of intervention measurements were used to calculate anthropometric gains and recovery from underweight, wasting and stunting. Mean weight-for-age increased by 0.22 (95% CI 0.07-0.37) and 0.28 (0.18-0.40) Z-score units in the LP and FS groups respectively. Comparable increase for mean weight-for-length was 0.39 (0.20-0.57) and 0.52 (0.38-0.65) Z-score units. Recovery from underweight and wasting was 20% and 93% in LP group and 16% and 75% in FS group. Few individuals recovered from stunting and mean length-for-age was not markedly changed. There were no statistically significant differences between the outcomes in the two intervention groups. In a poor food-security setting, underweight infants and children receiving supplementary feeding for 12 weeks with ready-to-use FS or maize-soy flour porridge show similar recovery from moderate wasting and underweight. Neither intervention, if limited to a 12-week duration, appears to have significant impact on the process of linear growth or stunting.

Milk--the promoter of chronic Western diseases

Common chronic diseases of Western societies, such as coronary heart disease, diabetes mellitus, cancer, hypertension, obesity, dementia, and allergic diseases are significantly influenced by dietary habits. Cow's milk and dairy products are nutritional staples in most Western societies. Milk and dairy product consumption is recommended by most nutritional societies because of their beneficial effects for calcium uptake and bone mineralization and as a source of valuable protein. However, the adverse long-term effects of milk and milk protein consumption on human health have been neglected. A hypothesis is presented, showing for the first time that milk protein consumption is an essential adverse environmental factor promoting most chronic diseases of Western societies. Milk protein consumption induces postprandial hyperinsulinaemia and shifts the growth hormone/insulin-like growth factor-1 (IGF-1) axis to permanently increased IGF-1 serum levels. Insulin/IGF-1 signalling is involved in the regulation of fetal growth, T-cell maturation in the thymus, linear growth, pathogenesis of acne, atherosclerosis, diabetes mellitus, obesity, cancer and neurodegenerative diseases, thus affecting most chronic diseases of Western societies. Of special concern is the possibility that milk intake during pregnancy adversely affects the early fetal programming of the IGF-1 axis which will influence health risks later in life. An accumulated body of evidence for the adverse effects of cow's milk consumption from fetal life to childhood, adolescence, adulthood and senescence will be provided which strengthens the presented hypothesis.

Postintervention growth of Malawian children who received 12-mo dietary complementation with a lipid-based nutrient supplement or maize-soy flour

BACKGROUND

Therapeutic feeding with micronutrient-fortified lipid-based nutrient supplements (LNSs) has proven useful in the rehabilitation of severely malnourished children. We recently reported that complementary feeding of 6-18-mo-old infants with an LNS known as FS50 was associated with improved linear growth and a reduction in the incidence of severe stunting during the supplementation period.

OBJECTIVE

Our objective was to assess whether a reduction in stunting seen with 12-mo LNS supplementation was sustained over a subsequent 2-y nonintervention period.

DESIGN

One hundred eighty-two 6-mo-old healthy rural Malawian infants were randomly assigned to receive daily supplementation for 12 mo with 71 g of maize-soy flour [likuni phala (LP); control group, 282 kcal] or either 50 g of FS50 (264 kcal; main intervention group), or 25 g of FS25 (130 kcal). Main outcome measures were incidence of severe stunting and mean z score changes in weight-for-age, length-for-age, and weight-for-length during a 36-mo follow-up period.

RESULTS

The cumulative 36-mo incidence of severe stunting was 19.6% in LP, 3.6% in FS50, and 10.3% in FS25 groups (P = 0.03). Mean weight-for-age changes were -1.09, -0.76, and -1.22 (P = 0.04); mean length-for-age changes were -0.47, -0.37, and -0.71 (P = 0.10); and mean weight-for-length changes were -1.52, -1.18, and -1.48 (P = 0.27). All differences were more marked among individuals with baseline length-for-age below the median. Differences in length developed during the intervention at age 10-18 mo, whereas weight differences continued to increase after the intervention.

CONCLUSIONS

Twelve-month-long complementary feeding with 50 g/d FS50 is likely to have a positive and sustained impact on the incidence of severe stunting in rural Malawi. Half-dose intervention may not have the same effect. This trial was registered at (clinicaltrials.gov) as NCT00131209.

Weight loss and the effect on stature in children during a residential intervention program

Weight loss is generally high in residential weight-loss programs but the effect of a large weight loss on linear growth is not known. We report the weight loss and the influence on linear growth in a large group of children during a residential weight-loss program focusing on nutrition and physical activity. In a longitudinal noncontrolled intervention study of 990 overweight children (540 girls) attending the weight reduction program from 1990 to 2001 for about 11 weeks (age: 10-14 years, mean BMI-standard deviation score (SDS) at enrollment: 2.83) weight and height were measured initially and after end of treatment. Weekly measurements of height and weight were performed on 138 children. The children lost on average 9.4 kg, reduced their BMI by 4.5 kg/m(2) and BMI-SDS by 0.98. In a multiple regression analysis (P < or = 0.001) weight loss was higher in boys than girls (1.7 kg), higher if the weight was higher at admission (-0.192 kg/kg at baseline) and was positively associated with duration of stay (-80 g/day). Initially the boys' BMI-SDS was higher than the girls' BMI-SDS (P < or = 0.05) but after 8 weeks of treatment the boys had lower BMI-SDS than the girls. There was no negative effect on linear growth during the treatment; on the contrary, linear growth accelerated during the stay as the average increase in height was 2.38 cm corresponding to 11.4 cm/year. In conclusion the children lost close to 1 kg/week during the stay without any negative effect on linear growth. The cause of the linear growth acceleration needs further investigation.

Milk consumption: aggravating factor of acne and promoter of chronic diseases of Western societies

Consumption of cow's milk and cow's milk protein result in changes of the hormonal axis of insulin, growth hormone and insulin-like growth factor-1(IGF-1) in humans. Milk consumption raises IGF-1 serum levels in the perinatal period, adolescence and adulthood. During puberty with the physiological onset of increased secretion of growth hormone, IGF-1 serum levels increase and are further enhanced by milk consumption. IGF-1 is a potent mitogen; after binding to its receptor in various tissues, it induces cell proliferation and inhibits apoptosis. Keratinocytes and sebocytes, as well as the androgen-synthesizing adrenals and gonads, are stimulated by IGF-1. The epidemic incidence of adolescent acne in Western milk-consuming societies can be explained by the increased insulin- and IGF-1-stimulation of sebaceous glands mediated by milk consumption. Acne can be regarded as a model for chronic Western diseases with pathologically increased IGF-1-stimulation. Many other organs, such as the thymus, bones, all glands, and vascular smooth muscle cells as well as neurons are subject to this abnormally increased hormonal stimulation. The milk-induced change of the IGF-1-axis most likely contributes to the development of fetal macrosomia, induction of atopy, accelerated linear growth, atherosclerosis, carcinogenesis and neurodegenerative diseases. Observations of molecular biology are supported by epidemiologic data and unmask milk consumption as a promoter of chronic diseases of Western societies.

The use of whey or skimmed milk powder in fortified blended foods for vulnerable groups

Fortified blended foods (FBF), especially corn soy blend, are used as food aid for millions of people worldwide, especially malnourished individuals and vulnerable groups. There are only a few studies evaluating the effect of FBF on health outcomes, and the potential negative effect of antinutrients has not been examined. Different lines of evidence suggest that dairy proteins have beneficial effects on vulnerable groups. Here we review the evidence on the effects of adding whey or skimmed milk powder to FBF used for malnourished infants and young children or people living with HIV or AIDS. Adding whey or skimmed milk powder to FBF improves the protein quality, allowing a reduction in total amount of protein, which could have potential metabolic advantages. It also allows for a reduced content of soy and cereal and thereby a reduction of potential antinutrients. It is possible that adding milk could improve weight gain, linear growth, and recovery from malnutrition, but this needs to be confirmed. Bioactive factors in whey might have beneficial effects on the immune system and muscle synthesis, but evidence from vulnerable groups is lacking. Milk proteins will improve flavor, which is important for acceptability in vulnerable groups. The most important disadvantage is a considerable increase in price. Adding 10-15% milk powder would double the price, which means that such a product should be used only in well-defined vulnerable groups with special needs. The potential beneficial effects of adding milk protein and lack of evidence in vulnerable groups call for randomized intervention studies.

Early protein intake and later obesity risk: which protein sources at which time points throughout infancy and childhood are important for body mass index and body fat percentage at 7 y of age?

BACKGROUND

A high early protein intake has been proposed to increase obesity risk.

OBJECTIVE

We examined whether a critical period of protein intake for later obesity may exist early in childhood and investigated the relation between protein intake from different sources and body mass index SD score and body fat percentage (BF%) at 7 y of age.

DESIGN

The study population included 203 participants of the Dortmund Nutritional and Longitudinally Designed Study with information on diet at 6 mo, 12 mo, 18-24 mo, 3-4 y, and 5-6 y. Life-course plots were constructed to assess when protein intake (% of energy) was associated with body mass index SD score and BF% at 7 y. Mean values were then compared among tertiles (T1-T3) of protein from different sources at the important time points.

RESULTS

The ages of 12 mo and 5-6 y were identified as critical ages at which higher total and animal, but not vegetable, protein intakes were positively related to later body fatness. In fully adjusted models, animal protein intake at 12 mo was associated with BF% at 7 y as follows [x (95% CI) BF%]: T1, 16.20 (15.23, 17.25); T2, 17.21 (16.24, 18.23); T3, 18.21 (17.12, 19.15); P for trend = 0.008. With respect to food groups, dairy, but not meat or cereal protein intake, at 12 mo was related to BF% at 7 y (P for trend = 0.07). Animal protein at 5-6 y yielded similar results (P for trend = 0.01), but food group associations were less consistent.

CONCLUSION

A higher animal, especially dairy, protein intake at 12 mo may be associated with an unfavorable body composition at 7 y. The age of 5-6 y might represent another critical period of protein intake for later obesity risk.