Written by: Anna Petherick, Ph.D. | Issue # 46 | 2016
- The first quantitative global estimates of the consumption of milk and other non-alcoholic beverages have been calculated.
- Unsurprisingly, milk drinking—and calcium consumption—correlates closely with national per capita income.
- The global average calcium consumption is far below the level recommended for adults by the US National Institutes of Health.
- Perhaps more concerning, young adults appear to be drinking relatively little milk and far larger volumes of sugary drinks, which may bode ill for their bone health later in life.
The most extensive and sophisticated attempt to quantify the consumption of milk by people over the age of 20, living in all corners of the globe, was recently published [1]. Its key implication is that average milk intake—and the average consumption of calcium—by both sexes, living in high, middle and low-income regions of the world, is less than commonly cited recommended levels.
The work’s other main finding is that milk consumption is much higher among older than younger adults in every one of 21 geographic subdivisions of the globe. On the one hand, this suggests that the elderly may be responding to nutritional advice to improve bone health, and protecting themselves against diseases like osteoporosis. On the other hand, however, it may reflect shifting habits. Since younger adults are also consuming far more fruit juice and sugar-sweetened beverages than older generations, less healthy drinks like sodas may be replacing milk in their diets, a tendency that may—worryingly—follow them into old age and leave them deficient in the raw materials of strong and healthy bones.
The research, which formed part of a wider effort to better understand the role of diet in the global distribution of disease burden, called NutriCoDE, was recently published in the journal, Plos One [1]. The raw milk consumption data came from 75 global surveys conducted between 1990 and 2010, involving almost 700,000 people. This raw data was subjected to complex statistical techniques that take into account differences in the way it was collected—allowing for the comparison of information from places with plenty of available measures of milk consumption, with information from places like Oceania and much of sub-Saharan Africa, where individual-level milk intake data is sparse.
According to the study authors, Gitanjali Singh of Tufts University, Boston, and her colleagues, the results offer “the first quantitative estimates of non-alcoholic beverage consumption in 187 countries of the world, and provide information that can inform several areas of global health.”
In 2010, adults over the age of 20 consumed on average 0.57 of an 8-oz serving of milk per day, which is about 135 ml. The global average daily consumption of calcium was 629 mg, which, although country-specific recommendations should vary with typical levels of sun exposure and other considerations, is nonetheless far below the 1,000 to 1,300 mg that is recommended by the US National Institutes of Health (NIH).
Generally, differences in milk consumption between men and women were slight. But the rich have far more milk in their diets than the poor. In high-income countries taken together, people drank about 170 ml of milk per day (5.8 oz) on average, whilst in low-income countries, the mean was 71 ml (2.4 oz). Similarly, mean calcium intake in high-income countries was 782 mg, but just 456 mg in low-income nations.
These broad categories of milk consumption mask wide variations among individual countries, though. The world’s most enthusiastic milk consumers in 2010 were Swedish and Icelandic women over 80 years old. They drank about 568 ml (19 oz) of milk per day. By comparison, men in North Korea—a country in which many hundreds of thousands of people are estimated to have died from famine in the 1990s, and where food shortages continue to this day—are thought to have consumed an average of only about 14 ml (or less than half an ounce) of milk. Such geographic patterns most likely reflect various influences, from milk availability, the commonality of alternatives (such as soy-based products), and the frequency of lactose intolerance among local populations.
Ultimately, the study authors hope that their work will make it possible to estimate the impact of beverage consumption on disease burdens around the world, and from that, make policy recommendations and corrections. Although not included in their analyses to date, they also note that global data on what children are drinking is currently being collected. Since teenagers are supposed to take in more calcium than adults—pregnant women aside—such data might make policymakers scratch their heads as to how to encourage teens to drink more milk and less sugary soft drinks.
References
1. Singh, G. M. et al. 2015. Global, regional and national consumption of sugar-sweetened beverages, fruit juices, and milk: A systematic assessment of beverage intake in 187 countries. Plos One. DOI:10.1371/journal.pone.0124845
Photo credit: Singh, G. M. et al. 2015