Free-living Adults Research Articles

Collection of free-living nymphs and adults of Amblyomma hebraeum (Acari: Ixodidae) with pheromone/carbon dioxide traps at 5 different ecological sites in heartwater endemic regions of South Africa.

The capture of free-living adults and nymphs of Amblyomma hebraeum, the main vector of heartwater in domestic and wild ruminants in South Africa, by means of attraction-aggregation-attachment-pheromone/carbon dioxide traps at five endemic localities in South Africa is described. Although the traps were used successfully at each of the localities, no determination of their efficiency in relation to the actual abundance of ticks at a particular site was made. This study confirmed that the traps could be used in a variety of ecological areas to locate populations of free-living adult A. hebraeum.

Longevity and ageing in parasitic and free-living nematodes.

In the developing field of biological gerontology, rapid advances have recently been made in the genetics of ageing in the nematode Caenorhabditis elegans. The aim of this work is to develop an understanding of the general mechanisms determining the ageing process. Within the last decade the prospect of actually achieving this somewhat hubristic aim has begun to look startlingly real. In this context, knowledge of every aspect of the biology of ageing in nematodes is of added interest. Here the patterns of ageing observed among parasitic and free-living nematodes are surveyed and compared. Like insects, nematode species exhibit enormous differences in the rate of ageing, with maximum life spans varying over more than a 1000-fold range, from three days in free-living Rhabdias bufonis adults, to at least 15 years in the filarial parasite Loa loa. The possible evolutionary and mechanistic causes of such differences in ageing are discussed.

Lack of effect of dietary chromium supplementation on glucose tolerance, plasma insulin and lipoprotein levels in patients with type 2 diabetes.

Chromium is essential for the regulation of insulin action, thereby influencing carbohydrate and lipid metabolism. An uncontrolled pilot study was designed to measure the habitual daily intake of chromium in a group of healthy individuals with type 2 diabetes and to monitor the effect of daily supplementation with high chromium yeast on glucose tolerance, plasma insulin and lipoproteins. Twelve free-living adults with type 2 diabetes underwent a glucose tolerance test (GTT) on recruitment, at 4 weeks (after a 7-d duplicate diet collection) and at 12 weeks (following 8 weeks daily supplementation with 100 micrograms of chromium). Urine samples were collected on the day before and the day of each GTT. Blood samples were taken at half hourly intervals for 3 hours during the GTT and the plasma glucose, cholesterol, triglyceride, HDL, LDL and insulin concentration measured. The chromium content of diets and urine samples was determined. Fasting glucose concentrations and glucose area under the curve profiles did not alter significantly post supplementation with the chromium rich yeast. No significant changes in insulin and lipoprotein concentrations were observed. The results of this study do not support the hypothesis that individuals with type 2 diabetes benefit from yeast-based chromium supplements (100 micrograms/day).

Physical activity in the prevention and treatment of obesity and its comorbidities: evidence report of independent panel to assess the role of physical activity in the treatment of obesity and its comorbidities.

Physical activity in the prevention and treatment of obesity and its comorbidities: evidence report of independent panel to assess the role of physical activity in the treatment of obesity and its comorbidities.

Chemo- and thermosensory neurons: structure and function in animal parasitic nematodes

Nematode parasites of warm-blooded hosts use chemical and thermal signals in host-finding and in the subsequent resumption of development. The free-living nematode Caenorhabditis elegans is a useful model for investigating the chemo- and thermosensory neurons of such parasites, because the functions of its amphidial neurons are well known from laser microbeam ablation studies. The neurons found in the amphidial channel detect aqueous chemoattractants and repellants; the wing cells—flattened amphidial neurons—detect volatile odorants. The finger cells—digitiform amphidial neurons—are the primary thermoreceptors. Two neuron classes, named ADF and ASI, control entry into the environmentally resistant resting and dispersal dauer larval stage, while the paired ASJ neurons control exit from this stage. Skin-penetrating nematode parasites, i.e. the dog hookworm Ancylostoma caninum, and the threadworm, Strongyloides stercoralis, use thermal and chemical signals for host-finding, while the passively ingested sheep stomach worm, Haemonchus contortus, uses environmental signals to position itself for ingestion. Amphidial neurons presumably recognize these signals. In all species, resumption of development, on entering a host, is probably triggered by host signals also perceived by amphidial neurons. In the amphids of the A. caninum infective larva, there are wing- and finger-cell neurons, as well as neurons ending in cilia-like dendritic processes, some of which presumably recognize a sequence of signals that stimulate these larvae to attach to suitable hosts. The functions of these neurons can be postulated, based on the known functions of their homologs in C. elegans. The threadworm, S. stercoralis, has a complex life cycle. After leaving the host, soil-dwelling larvae may develop either to infective larvae (the life-stage equivalent of dauer larvae) or to free-living adults. As with the dauer larva of C. elegans, two neuron classes control this developmental switch. Amphidial neurons control chemotaxis to a skin extract, and a highly modified amphidial neuron, the lamellar cell, appears to be the primary thermoreceptor, in addition to having chemosensory function. The stomach worm, Haemonchus contortus, depends on ingestion by a grazing host. Once ingested, the infective larva is exposed to profound environmental changes in the rumen. These changes stimulate resumption of development in this species. We hypothesize that resumption of development is under the control of the ASJ neuronal pair. Identification of the neurons that control the infective process could provide the basis for entirely new approaches to parasite control involving interference with development at the time and place of initial host-contact.

Equations for predicting the energy requirements of healthy adults aged 18–81 y

Recent studies have questioned the accuracy of using the current recommended dietary allowances (RDAs) to predict usual energy requirements in adults. We developed equations to predict adult energy requirements from simple anthropometric and laboratory measures by using the doubly labeled water method to determine each subject's total energy expenditure (TEE), which is equal to usual energy requirements in weight-stable individuals. This was a cross-sectional study conducted with 93 healthy, free-living adults [44 men and 49 women; body mass index range (in kg/m2): 18.4-31.8] aged 18-81 y. Body fat and fat-free mass were measured by underwater weighing, physical activity was estimated by using activity monitors, and resting energy expenditure was determined by indirect calorimetry. Information on anthropometric variables and reported strenuous activity was also collected. Three regression equations were developed and verified for accuracy by using bootstrap analysis and doubly labeled water data published by other research groups. The first equation used information on only age, weight, height, and sex and had an SEE for prediction of TEE of 1.80 MJ/d. The second and third equations used different combinations of basic and laboratory data and had SEEs of 1.55 and 1.65 MJ/d, respectively. With use of the same analytic approaches, the RDAs for energy were shown to significantly underestimate usual energy needs by approximately 10%; the extent of underestimation was significantly greater for subjects with high TEEs than for subjects with low TEEs. Regression equations based on doubly labeled water measurements of TEE appear to be more accurate than the current RDAs for predicting energy requirements in healthy, nonobese adults living in affluent countries.

Salt-sensitivity classification in normotensive adults

The objectives of this study were to assess the reliability, sensitivity and specificity of salt-sensitivity classification in normotensive adults and to determine the predictive power of four clinical indices for salt-sensitivity. A total of 66 healthy, normotensive, free-living adults were administered 11-day salt-sensitivity diagnostic dietary salt challenges on two occasions to permit assessment of classification test-retest reliability. An oral glucose tolerance test, an acute saline loading test, gustatory testing and determination of salivary flow and sodium concentration were carried out to assess (by correlation analysis) their predictive power for salt-sensitivity. Following these procedures, 21 participants followed a reduced-sodium diet for 4 months, during which blood pressure was monitored monthly to allow evaluation of salt-sensitivity classification sensitivity and specificity. Regression was used to develop a predictive model for salt-sensitivity. Salt-sensitivity classification was not highly reliable (kappa-value=0.38), sensitive (0.73) or specific (0.60). No single index was highly predictive of classification status, but a model composed of five indices accounted for 92% of the variance in blood pressure response to acute salt challenge. The dietary salt challenge procedure used here for salt-sensitivity classification of normotensive adults had low test-retest reliability. While a battery of easily measured attributes may facilitate rapid salt-sensitivity classification, such a diagnosis provides only limited insight regarding blood pressure responsiveness to chronic dietary salt restriction in normotensive adults.

ICHTHYOXENUS FUSHANENSIS, NEW SPECIES (ISOPODA: CYMOTHOIDAE), PARASITE OF THE FRESH-WATER FISH VARICORHINUS BARBATULUS FROM NORTHERN TAIWAN

Ichthyoxenusfushanensis, new species, a flesh-burrowing parasite of Varicorhinus barbatulus, collected from a mountain stream in northern Taiwan, is described. It resembles the only congeneric species, I. formosanus, recorded in Taiwan, but can be distinguished from the latter by the narrower forehead, smooth posterior margin of pereionites, narrower pleotelson, shorter antennae 1 and 2, and short carpus of pereiopod 1. The two species also differ in the structure of the mouthparts, especially the number of terminal spines on the mandible and maxilliped. In addition, the two species occur in different habitats and on different hosts. Ichthyoxenus formosanus is found in the body cavity of the fresh-water carp, Carassius auratus, occurring in lakes or ponds. The morphological differences between free-living mancas and parasitic adults of Ichthyoxenus fushanensis are compared. An undescribed cymothoid isopod of the genus Ichthyoxenus Herklots, 1870, was recently recovered from the fresh-water fish, Varicorhinus barbatulus (Pellegrin, 1908), in a mountain stream at Fushan Village, Wulai, Taipei County, in northern Taiwan. Ichthyoxenus is a genus of parasitic isopods that live on a variety of fresh-water and marine fishes. The distribution patterns and habitats of the

Effects of Age and Captivity on Plasma Chemistry Values of the Egyptian Vulture

Despite the interest in blood chemistry for studying ecological and pathological characteristics of birds, sources of variability such as age and captivity are poorly understood, and reference values usually are obtained from adult captive birds. We determined 15 plasma chemical variables for 164 free-living Egyptian Vultures (Neophron percnopterus) of three age groups (nestlings, subadults, and adults), and for 9 captive adults. Free-living subadults and adults exhibited identical plasma chemistry values. Nestlings had significantly higher levels of creatinine, urate, urea, triglycerides, calcium, phosphorus, and alkaline phosphatase (AP) than both free-living subadults and adults, but lower values of glucose and aspartate aminotransferase (AST). Captive adults had significantly higher levels of total protein, albumin, creatinine, urate, cholesterol, calcium, phosphorus, and AST than free-living adults, which we attribute to differences in diet quality and physical activity. We conclude that future studies should consider age as a major source of variability in avian plasma chemistry, and that results obtained from captivity should be used cautiously to interpret plasma chemistry in the study and rehabilitation of wild birds.

THE RELATIONSHIP OF SELF-EFFICACY, EDUCATION, AND SOCIAL SUPPORT TO REGULARLY EXERCISING OLDER ADULTS

687 Current evidence in the exercise adherence literature suggests that both high self-efficacy and a strong perception of social support are key factors to continued physical activity. Further, research indicates that regular participation in exercise is also associated with a high level of formal education. The purpose of this study was to explore the relationships between these factors and regular elderly exercisers. Thirty-five free-living older adults ([horizontal bar over]x.=71 yr.) were surveyed on their stage of exercise behaviour change, exercise self-efficacy, and years of formal education using a questionnaire-based design distributed at two recreation centers. Perceived sources of social support to exercise were also investigated in the context of past and present peer and family support, as well as physician encouragement towards physical activity. All participants proved to be regular exercisers (in the maintenance stage of behaviour change) and responded with moderately high scores in self-efficacy (70%), and many years of formal education (average = university graduation). High scores were also reported in the perception of exercise social support (83%), and no significant differences were indicated among the four possible sources for support surveyed. Also, no gender differences were found among the subjects on association with all constructs. These findings are in agreement with the literature concerning the importance of self-efficacy, and social support for physical activity among older adults, and further indicate the association of education and regular exercise found in large epidemiological and cross-sectional survey studies.

A six-week randomized controlled trial of olestra or regular snack foods: Comparison of Gastro-intestinal symptoms in a large population

Background: Olestra is a new fat replacement that adds no calories to food. Because olestra is neither digested nor absorbed it has the potential for GI symptoms. We conducted a randomized, double-blind trial to determine the true incidence and impact of GI symptoms in free-living adults and children consuming olestra snacks ad libitum. Methods: 3,181 participants were randomized by household and consumed either olestra or regular full fat potato and corn chips in olestra-labeled packages. Participants could also choose additional full fat snacks in commercial packages. A household representative visited one of two central sites weekly, for 6 weeks, to select snacks and to return daily diaries. Each subject in the study recorded daily the amount of snacks consumed, GI symptoms, and the impact of symptoms on activities. Results: A total of 2,296 teens and adults (ages 13-89) and 885 children (ages 2-12) consumed test snacks during the study. There was no overall difference in GI symptoms. Of 1,620 individuals in the olestra group, 619 (38.2%) reported one or GI symptoms, compared to 576 (36.9%) of the 1,561 individuals consuming full fat snacks, p=0.60. There were also no significant differences between the olestra and full fat groups in the incidence of any one of 8 GI symptoms, except for increased nausea in the full fat group (Table). Mean number of symptom-days were not different between groups for any of the 8 GI symptoms, except for more frequent bowel movements (3.7 vs 2.8 days, olestra vs. full fat, p=0.04). There was no difference in the impact of symptoms on daily activities between the 2 groups. Of subjects who reported that they visited a physician for GI symptoms, 6 were in the olestra group and 10 in the full fat group. Test chips were consumed frequently throughout the study (mean 20.2 vs. 21.6 of 42 study days, for olestra and full fat). The frequency of consumption did not correlate with symptom reporting in either group.

Longitudinal changes in dehydroepiandrosterone concentrations in men and women

Dehydroepiandrosterone, an adrenal steroid, has many purported roles in the body and has been used as an oral supplement in the treatment of various illnesses. Because little is known about normal changes over time in dehydroepiandrosterone concentrations, we studied the 5-year change in plasma dehydroepiandrosterone concentrations in 614 free-living adults. Two hundred seventy-three males and 341 females had dehydroepiandrosterone and dehydroepiandrosterone sulfate concentrations measured in 1989 and 1994. Demographic data were also obtained. Dehydroepiandrosterone concentrations differed significantly by sex and 5-year age group. The average decline in dehydroepiandrosterone was 5.6%/year, and the rate of decline was directly related to age but not to sex, measures of adiposity, or serum glucose. Dehydroepiandrosterone sulfate concentrations differed significantly by sex and age group. The average decline in the sulfated hormone was 2.0%/year and was not related to age, sex, measures of adiposity, or serum glucose. Knowledge of the natural course of age-related changes in dehydroepiandrosterone and dehydroepiandrosterone sulfate concentrations is essential to our understanding of the relationship of dehydroepiandrosterone to chronic diseases.

Selected Mineral Intakes of Adult African-Americans in the Washington, DC Area

The objective of this study was to assess daily self-selected mineral intake of free-living African-American adults using the duplicate portion collection technique coupled with direct chemical analysis. A duplicate sample of every food and beverage consumed was collected by each subject. The collection period was for 3 days (Sunday, Tuesday, and Thursday) of 1 week in 1986. The chemical analysis included calcium, phosphorus, magnesium, sodium, potassium, manganese, iron, copper, zinc, and phytate. Forty adult African-Americans (20 females and 20 males) living in the Washington, DC area volunteered to participate. They were apparently healthy, ranging in age from 21 to 65 years, with a median age of 38.5 years. The analytical data from the daily food and beverage intake were compared with the Recommended Dietary Allowances (RDA)/ Estimated Safe and Adequate Daily Dietary Intakes (ESADDI). The results were also compared with data from the National Health and Nutrition Examination Survey (NHANES) III and USDA's Continuing Survey of Food Intakes by Individuals(USDA-CSFII 1989–91). Compared with the RDA/ESADDI, for women, the median intakes of less than two-thirds the recommendations were : calcium (54%), magnesium (65%), iron (61%), copper(60%), zinc (61%), and potassium (50%) as determined by chemical analysis. For the men, applying the same criteria, the minerals and percentages are: calcium (64%), magnesium (56%), copper (60%), zinc (61%), and potassium (58%). The phytate:zinc and phytate × Ca:Zn molar ratios suggested no general inhibition of zinc bioavailability despite some higher than suggested limiting molar ratios found in a few individual daily diets. Although limited in scope, these results suggest that African-American adults are selecting diets that are frequently low in specific minerals. Some of these essential nutrients have been implicated in chronic health problems prevalent in this ethnic group; e.g., hypertension and cardiovascular diseases. Therefore, nutritionists and other health professionals should emphasize the need for a wider selection of foods to prevent specific mineral deficits. These foods might include acceptable dairy products, meats/seafood, and mineral-fortified cereals/breads and juices.

Total Energy Expenditure in Adults with Cerebral Palsy as Assessed by Doubly Labeled Water

Objectives To characterize total energy expenditure (TEE) in free-living adults with cerebral palsy (CP) using the doubly labeled water technique, and to determine those physiologic variables and characteristics of CP that were markers of TEE in adults with CP. Design TEE was measured using the doubly labeled water technique in 30 free-living adults with CP (12 women, 18 men). To determine the best markers of TEE, the following factors were examined: CP status, resting metabolic rate (RMR), anthropomet-ric characteristics and body composition by means of dual-energy x-ray absorptiometry (DXA) and skinfold thickness measurements, energy cost of leisure-time activities, and oral-motor impairment. Statistical analysis Means±standard deviations, t tests, Pearson product-moment correlation coefficients, Spearman rank correlation coefficients, χ 2, stepwise multiple-correlation regression analysis, and analysis of covariance were used to examine the relationships among variables of interest. Results TEE was highly variable in the sample (mean=2,455±622 kcal/day for men and 1,986±363 kcal/day for women). Stepwise regression analysis showed that TEE was best predicted in the sample by RMR, percentage body fat determined by DXA, ambulation status, and sex (multiple R=.68, P=.003). When practical, easily measured variables were used, TEE was best predicted by height, ambulation status, percentage body fat by skinfold thickness measurements, and sex (multiple R=.61, P.=018). The contribution of energy expended in physical activity to TEE was significantly higher in the ambulatory subjects than the nonambulatory subjects (25% vs 16%, respectively; P=.009). Applications The high degree of variability in TEE, largely attributable to high interindividual variation in energy expended in physical activity, makes it difficult to provide general guidelines for energy requirements for adults with CP. Because ambulation status was an important predictor of TEE, it must be accounted for in estimating energy requirements in this population.

Olestra Affects Serum Concentrations of α-Tocopherol and Carotenoids but not Vitamin D or Vitamin K Status in Free-Living Subjects1–4

Normal, healthy, free-living adults ingested either 18 g/d olestra, with or without 1.1 mg tocopheryl acetate/g olestra, or 18 g/d triglyceride placebo, for 16 wk in a double-blind, placebo-controlled study. Serum concentrations of α-tocopherol, α-carotene, β-carotene, lycopene, lutein/zeaxanthin, retinol and cholesterol were measured biweekly. Serum 25-hydroxyvitamin D concentration, prothrombin time, partial thromboplastin time and plasma concentration of functional prothrombin (Simplastin-Ecarin assay) were measured at wk 0, 8 and 16. Relative to the placebo group, serum α-tocopherol concentration was reduced 6% for the group given 18 g/d olestra. Addition of tocopheryl acetate to olestra partially offset the effect of olestra. For the group given 18 g/d olestra plus 1.1 mg tocopheryl acetate/g olestra, serum α-tocopherol concentration was 4% less than the placebo value. Olestra reduced serum concentration of β-carotene by 27%; the other carotenoids were similarly affected. Serum cholesterol concentration was reduced ∼4.5% in the olestra groups, relative to placebo, but the differences were not significant. Serum triglycerides, serum 25-hydroxyvitamin D, prothrombin time, partial thromboplastin time or the plasma concentration of under-γ-carboxylated prothrombin were unaffected by olestra. Clinical observations and laboratory measures indicated no health-related effects of olestra; mild-to-moderate transient gastrointestinal symptoms such as bloating, cramping, loose stools and diarrhea were reported by all groups.

HOST IMMUNE STATUS DETERMINES SEXUALITY IN A PARASITIC NEMATODE.

We examine the hypothesis that sexual reproduction by parasites is an adaptation to counter the somatic evolution of vertebrate immune responses. This is analogous to the idea that antagonistic coevolution between hosts and their parasites maintains sexual reproduction in host populations. Strongyloides ratti is a parasitic nematode of rats. It can have a direct life cycle, with clonal larvae of the wholly parthenogenetic parasites becoming infective, or an indirect life cycle, with clonal larvae developing into free-living dioecious adults. These free-living adults produce infective larvae by conventional meiosis and syngamy. The occurrence of the sexual cycle is determined by both environmental and genetic factors. By experimentally manipulating host immune status using hypothymic mutants, corticosteroids, whole-body γ-irradiation and previous exposure to S. ratti, we show that larvae from hosts that have acquired immune protection are more likely to develop into sexual adults. This effect is independent of the method of manipulation, larval density, and the number of days postinfection. This immune-determined sexuality is consistent with the idea that sexual reproduction by parasites is adaptive in the face of specific immunity, an idea which, if true, has clinical and epidemiological consequences.

Acarine colonisation of Antarctica and the islands of the Southern Ocean: the role of zoohoria

AbstractA quarter of the terrestrial Acari recorded from Antarctica and the sub-Antarctic islands are parasitic haematophages or non-feeding phoretics associated with other larger and more mobile animals, especially sea birds and pterygote insects. Although flying sea birds are effective vectors of zoohoric mites into the region, penguins are not and merely serve as reservoir hosts. Similarly, most of the mites associated with insects were accidentally introduced by man as free-living adults that subsequently utilised a range of alien and indigenous insects as local dispersal mechanisms.

Infection of Ixodes ricinus (Acari:Ixodidae) by Borrelia burgdorferi in Ile de France.

Free-living nymphs and adults from Rambouillet and Fontainebleau, 2 major forests of Ile de France, were collected to determine the infection rates of Ixodes ricinus L. by Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt & Brenner). Field-collected I. ricinus nymphs and adults were screened for the presence of B. burgdorferi using direct fluorescent antibody assay. The infection rates of nymph, male and female were 12.4% (314), 2.8% (35), and 2.9% (34). No difference in infection rates of nymphs among sites were detected. Spirochetes was isolated from both sites. Isolates from Rambouillet and Fontainebleau were identified as B. burgdorferi sensu stricto and B. garinii, respectively (Baranton, Postic, Saint-Girons, Boerlin, Piffaretti, Assous, and Grimont).

Use of selenium concentration in whole blood, serum, toenails, or urine as a surrogate measure of selenium intake.

We examined the validity of using the selenium level in a single biological specimen as a surrogate measure of usual intake. We used data from 77 free-living adults from South Dakota and Wyoming. Subjects provided multiple 1-day duplicate-plate food composites, repeated specimens of blood and toenails, and 24-hour urine collections. We developed a statistical calibration method that incorporated measurement error correction to analyze the data. The Pearson correlation coefficients between selenium intake and a single selenium status measure, after deattenuation to adjust for the effect of within-person variation in intake, were: 0.78 for whole blood, 0.74 for serum, 0.67 for toenails, and 0.86 for urine. We present formulas to estimate the intake of individuals, based on selenium levels in a single specimen of blood, toenails, or urine. In these data, the concentration of selenium in a single specimen of whole blood, serum, or toenails served reasonably well as a measure for ranking subjects according to long-term selenium intake but provided only a rough estimate of intake for each subject.

How Much Lactose is Low Lactose?

Objective To test the hypothesis that complete elimination of lactose is not necessary to ensure tolerance by lactose maldigesters. Design Double-blind, randomized protocol in which challenge doses of 0, 2, 6, 12, and 20 g lactose in water were fed to subjects after a 12-hour fast. Subjects 13 healthy, free-living adults who were lactose maldigesters. Main outcome measures Breath hydrogen production (a measure of maldigestion) and symptom response to each challenge dose. Statistical analysis Analysis of variance was done to determine overall differences in mean hydrogen gas production (peak and sum of hours 1 through 8). Friedman's test was used to determine overall differences in the mean ranks for each symptom. Fisher's least significant difference test was used for multiple comparisons for hydrogen and symptom and data. Results Hydrogen production after consumption of the 0- and 2-g lactose doses was not significantly different. Hydrogen production increased with the 6-g dose. Intensity of abdominal pain increased when the dose of lactose was 12 g. Episodes of flatulence did not increase until the dose reached 20 g. No significant differences in the occurrence of diarrhea were observed after the five treatments. Conclusions No significant increase in breath hydrogen production or intolerance symptoms occurred after consumption of a 2-g dose of lactose. Up to 6 g was tolerated, even though maldigestion could be measured at the 6-g dose. Thus, lactose maldigesters may be able to tolerate foods containing 6 g lactose or less per serving, such as hard cheeses and small servings (120 mL or less) of milk. J Am Diet Assoc. 1996; 96:243-246.