Low Vs whole-fat dairy: No key differences in weight, waistline, lipid profiles among healthy kids – Three-month RCT
However, consuming reduced-fat dairy products did lead to a significantly lower total fat and saturated fat intake.
Based on the findings, a group of researchers from Edith Cowan University, University of Western Australia, and University of Washington suggested that healthy children “can safely consume” whole-fat dairy products without the fear of developing obesity or adverse health effects.
Writing in The American Journal of Clinical Nutrition, the researchers conducted a three-month double-blind randomised trial involving nearly 50 children between four and six years old.
In Australia, whole milk is considered essential for infant growth. However, individuals above two years old are advised to consume reduced-fat dairy products, due to the “adiposity hypothesis” and “saturated fat hypothesis”.
“The ‘adiposity hypothesis’ suggests that higher energy density in whole-fat dairy may increase ad libitum energy intake and body weight.
“The ‘saturated fat hypothesis’ considers that the 60 per cent to 70 per cent saturated fat fraction in dairy fat raises serum LDL cholesterol, considered a major risk factor for CVD [cardiovascular diseases],” the researchers explained.
However, the researchers also pointed out that existing observational studies have shown that encouraging reduced-fat dairy consumption was “unlikely to prevent or reduce childhood obesity”.
Hence, they have carried out a trial, titled the Milky Way study, to test whether reduced-fat dairy products would reduce chances of childhood obesity in children.
During the study, children who are habitual consumers of whole-fat dairy were randomly assigned to either 1) continuing consuming whole-fat dairy foods or 2) switch to reduced-fat versions of these dairy foods.
As part of the protocol, the kids were required to consume more than one serving of dairy products every day.
A serving could include a 250-ml glass of milk, 40g of cheese, or 200g tub of yogurt.
The kids’ body compositions and blood pressure were measured before and after the study, while blood test analysis was also conducted.
Fat consumption difference
There was a significantly lower total fat and saturated fat consumption in children taking reduced-fat dairy.
“Dairy fat intake was reduced by an adjusted 12.9 ± 4.1 g/d in the reduced-fat compared with the whole-fat dairy group, although participant dietary energy intakes remained similar… The dairy saturated fat fraction showed similar results.
“Our study demonstrated significant changes in dairy fat consumption over three months, supported by significant correlations of erythrocyte pentadecanoic acid with dairy fat intake. Despite this, daily energy intakes remained similar,” said the researchers.
Measuring erythrocyte or the red blood cells’ pentadecanoic acid levels is relevant in this case as dairy fat is the main source of pentadecanoic acid.
Sodium consumption difference
On the other hand, the kids consuming reduced-fat dairy had a higher intake of dietary sodium as compared to the group taking whole-fat dairy.
“The reduced-fat dairy group increased their intake of dietary sodium over the dairy intervention by 301 ± 109 mg/d.
“After adjustment for dietary energy, this amounted to a substantial increase in sodium intake compared with the whole-fat dairy group.
“When adjusted further for intake changes in dairy sodium, the reduced-fat dairy group effectively increased their dietary sodium by 241 mg/d (15.2 per cent) from baseline, amounting to an additional 44 mg/1000 kJ (15.6 per cent) consumed per day compared with the whole-fat group,” the researchers pointed out.
No significant differences
Aside from fat and sodium intake, there were no significant differences between the two groups in terms of their neck or waist circumference, weight, lipid profile, blood glucose level, and blood pressure.
“Fasting serum glucose and lipids in both Milky Way Study groups were not differentially affected by the dairy intervention: not even a trend was apparent,” the researchers highlighted.
However, they pointed out that both groups showed a similar, nonsignificant increase in LDL-cholesterol – the “bad” cholesterol – and a decline in HDL-cholesterol – the “good” cholesterol.
The findings were in line with two other interventions, which also found no significant differences in body weight, BMI, or waist circumference in children and teenagers consuming reduced-fat and whole-fat dairy products.
“Our RCT shows in addition no significant differences in body fat percentage or FMI, all in direct opposition to the so-called ‘adiposity hypothesis’,” the researchers concluded.
Source: The American Journal of Clinical Nutrition
Whole-fat dairy products do not adversely affect adiposity or cardiometabolic risk factors in children in the Milky Way Study: a double-blind randomized controlled pilot study
Authors: Analise Nicholl and et al