Dairy s Rich Nutrient Package Connie M. Weaver, Ph.D. Distinguished Professor Department Nutrition Science Purdue University, USA September 2013
Disclosures Boards NOF ILSI Showalter Pharmavite Grants NIH Dairy Research Institute Nestle Tate and Lyle
Outline Evolutionary history of milk drinking Intake and health Global intake and recommendations Source of nutrients Marker of a healthy diet Alternate sources of nutrients Future research needs
Dairy transition from hunting and gathering to agriculture Salque et al. Nature 493:533-25, 2013; Leonardi et al., J Int. Dairy J 22:88-97, 2012
Strong Milk Selective Pressure Convergent evolution Culture Pastoralism ~9000 years ago Fermentation of milk ~8000 years ago Genetics Lactase Persistence Lactose glu + gal Lactase 2002 lactase gene discovered in Europe SNP LCT Mutation ~7500 years ago in Hungary 3 distinct SNPs in Africa* 35% population LP *Tishoff et al., Nature Genet 39:36, 2007
Strong Milk Selective Pressure Convergent evolution Culture Genetics Health Source of nutrients Bioactives Independence of Mothers Fertility selection offspring 19% Occupation
Dairy and Growth and Development In developing countries Dairy consumption increases linear growth Pastoral people taller In developed countries Milk consumption more modestly related to height Source of energy IGF-1 Source of concern
Undernutrition in kids or adults Enteral feeding products are based on milk
Peak skeletal mass achieved by ages 20-30 Adult skeleton remodeled and replaced every 10 years Growth Peak bone mass Maintenance Menopause Puberty Frailty Old Age 2004 Nutrition and Bone. MRC Human Nutrition Research Cambridge UK. (Gail Goldberg)
IGF-I Ca Utilization Estrogen Estrogen Bone resorption Ca suppresses bone resorption
There is much confusion in the literature about dairy and bone Life stage, sex, genetic dependent Methods for assessing intake weak Poor compliance and baseline status in RCTs
Calcium Bioavailability from Milk at Different Lifestages Calcium Absorption ~80% Calcium Absorption ~30% Calcium Absorption ~25% Calcium Absorption ~40%
Meta analysis of prospective cohort studies No overall association between milk intake and hip fracture in women But possibly men No meta-analysis of RCTs of dairy intake and fracture Bischoff-Ferrari, et al., JBMR 26:833, 2011
Children who avoid milk are at Risk for bone fracture Milk avoider s Fracture Risk 34.8% Birth cohort 13.0% Goulding et al. JADA 104:250, 2004 Goulding et al. JADA 104:250,2004
Houkanen et al. Bone 21:473, 1997 Lactose Intolerance & Fracture in Finnish Women 38-57 y N=11,619 N=1,299 fracture 1980-1989 N=896 Lactose intolerant Lactose Lactose Intolerant Tolerant Dairy Ca (mg/d) 570 850 Fracture OR 1.33 (1.09-1.62) Lower body excluding ankle OR 2.15 (1.53-3.04)
EFFECT Threshold Nutrients and Study Design the control group must be deficient INTAKE When baseline intakes are low, significant effects more likely
Total body BMD in 698 rural Indian children at 6 yr related to maternal milk intake diet at 28 wk gestation Total body BMD in children g/cm 2 Once a day or less Up to twice a day Up to 3 times a day More than 3 times a day P<0.02 Frequency of consumption by mother Ganpule et al. J Clin Endocrinol Metab 91:2994, 2006.
18 mo RCT of milk (1 pint) on BMC in 82 white girls aged 12.2 y with baseline calcium intakes of 740 mg/d Percentage Increase 0 6 12 18 Cadogan J, et al. BMJ 1997;315:1255-60. Total BMC
2 year RCT of milk supplementation (1200 mg Ca/d) BMD of spine and hip in 173 postmenopausal Chinese women Chee et al. Osteoporosis Intl 14:828, 2003
Adult milk intake recommendations by country Most require 2-3 servings/day 2 servings/d 2-3 servings/d 3 servings/d Bulgaria Australia Austria Denmark Canada Chile Finland Portugal France Greece Turkey India Hungary Ireland Japan Italy Poland Japan South Africa (1-2) Switzerland Sweden United States Thailand (1-2) Uruguay.
8-ounce cups, per day Fluid milk consumption is decreasing in Americans in all age groups 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 Adolescents and adults Children (2 to 12 years) Americans of all ages 1977-78 1989-91 1994-96 2003-04 2007-08 Survey years
Worldwide Total Milk Consumption per capita
Milk as a Source of Nutrients 3 cups low-fat milk provide about: Calcium >100% Phosphorus 99% Vitamin D 86% Protein 54% Riboflavin 32% Potassium 28% Magnesium 25% Vit B, Vit A, Zinc, and more Percentages for vit D and calcium based on EAR, percentages for all others based on RDA
% of Calories and Nutrients from Dairy in US Diet (>2 yrs age)
Role of milk products in intakes of shortfall nutrients % of recommendation in children 160 140 120 100 80 60 40 20 0 With= 2.5-3.5 serving/d Without= <1 serving/d Calcium Potassium Magnesium Calcium Potassium Magnesium 2-8 y 9-18 y Age Group Nicklas et al JACN 2009; 28:73S-81S
Nutrient Rich Foods Nutrient density scoring (NRF 9.3) 9 nutrients to encourage 3 nutrients to limit Protein Fiber Vitamin A Saturated Fat Iron Calcium Vitamin C Added Sugars Potassium Magnesium Vitamin E Sodium 27 Courtesy of Victor Fulgoni
Yogurt Consumption Associated with Better Diet Quality Framingham Heart Study Offspring n=6526consumers (64% women, 41% men) Wang et al., Nutr Res 33:16, 2013
Milk: Source of Bioactives for Health CLA Amino acids, protein constituents Oligoosaccharides
Mechanistic Outcomes Predicted effects of GOS on Calcium Absorption and BMD in Rats GOS Cecal ph* (2.2 to 11.0 % change) Cecal Wall Weight* (13.3 to 141.0 % change) Cecal Content Weight* (45.0 to 342.6 % change) Bifidobacteria (-25.4 to +265.9 % change) Calcium Absorption* (15.7 53.2 % change) Mg absorption also Bone Mineral Density (1.8 3.1 % change) * p<0.01, p<0.05, p<0.0001 Weaver et al. J Agric Food Chem 2011; 59: 6501
Nutrient Adequacy Without Dairy Closest Food Alternative - calcium-fortified soy milk 3 cup comparison Cow s milk Soy Milk (Differences from cow s milk) Cow Milk Soy Milk 1104 mg Ca 675 mg P 22.1 g protein 675 mg K 117 mg Mg 1.58 mg riboflavin 360 IU vitamin D (in N. America) +233 mg -20 mg -2.6 g -423 mg +36 mg +0.23 mg -20 IU
% Foods Vary in Calcium Bioavailability 35 30 25 20 15 10 5 0 Milk * p<0.0001 Spinach Nickel et al. J Nutr 126:1406, 1996 Weaver and Heaney Calcif Tissue Int. 49:244, 1991
Food sources of bioavailable calcium Calcium Estimated # Servings Content Fractional Absorbable needed to Food Serving Absorption Ca/serving = 1 c. milk (mg) (%) (mg) Milk, yogurt 300 32.1 96.3 1.0 Beans, dried 50 15.6 7.8 12.3 Broccoli 35 61.3 21.5 4.5 Cabbage 79 52.7 41.6 2.3 Kale 47 58.8 27.6 3.5 Spinach 122 5.1 6.2 15.5 Tofu, calcium set 258 31.0 80.0 1.2
Sources Milk Calcium Weaver et al., JBMR 24:1411-1419, 2009
Comparison of Milk and Supplement Ca on Bone Objectives 1. To directly compare NFDM and CaCO 3 for bone acquisition in growing female rats. 2. To determine any protection of early feeding of NFDM and CaCO 3 on bone maintenance in mature rats. Weaver et al., JBMR 24:1411-1419, 2009
Experimental Design Weanling rats 10 weeks* 20 weeks 0.4% Ca as CaCO 3 n=150 0.4% Ca as NFDM n =150 0.2% Ca as CaCO3 n=50 0.4% Ca as CaCO3 n=50 0.2% Ca as CaCO3 n=50 0.4% Ca as NFDM n=50 *50 of each group sacrificed at 10 wk Weaver et al., JBMR 24:1411-1419, 2009
Benefit of NDFM over CaCO 3 in Growing Rats % advantage of NFDM Diet over CaCO 3 14 12 10 8 6 4 2 0 *p<0.05 **p<0.01 ***p<0.0001 * length *** width ** dry wt *** *** uw wt ** total bone density ultimate load *** Ca/bone ** Cort. Th Weaver et al., JBMR 24:1411-1419, 2009
Mature Rats
Advantages to femur of early feeding NFDM over CaCO 3 switched to low CaCO 3 diets 20 20 % advantage on NFDM over CaCO 3 18 16 14 12 10 10 8 6 4 2 0 8 6 4 2 0 ** ** ** * ** *p<0.02, **p<0.0001 Weaver et al., JBMR 24:1411-1419, 2009
Milk during growth confers substantial benefits to bone over nutritionally adequate diets that help protect against Ca deficits later in life. Weaver et al., JBMR 24:1411-1419, 2009
Conclusions Dairy culture and lactase persistence co-evolved. Milk/milk products = the best & most economical source of many limiting nutrients. Most countries recommend 2-3 servings/day. Diets low in dairy tend to be poor in Ca, K, vitamin D & many other nutrients. Nutrients in milk exhibit thresholds for health benefits so research showing benefits of adding dairy products to diets more apparent in poor quality diets. Milk as a source of calcium during growth results in bigger, denser, stronger bones than calcium supplements & protects against calcium deficiency later in life in animals, but shorter term trials and prospective studies inconclusive.
Future Needs Meta analysis RCTs dairy and bone Role of dairy, gut microbiota, and health