If you consider the total amount of energy used to produce, transport, and dispose of each container, as well as how each affects what’s inside it, paperboard cartons are better for both the environment and your health.

Lifecycle energy consumption includes what’s required to make the container, transport it from dairies to retail outlets, collect it once it’s waste, and recycle or dispose of it. Several studies conclude that plastic milk jugs consume more than 20 percent more lifecycle energy than do paperboard cartons, and use energy that comes almost exclusively from fossil fuels (largely because plastic is made from petroleum). Paperboard cartons, on the other hand, are produced from trees. While it’s not a great trade-off to turn living trees into cartons, trees are at least renewable, unlike the petroleum.

Also, plastic milk jugs are typically more likely to be recycled than cardboard cartons. But because most plastics are recycled into a weaker grade of plastic resin, most second-generation plastic is dumped in a landfill. In addition, sanitation concerns prevent recycled plastic from being used in containers that have direct contact with food. So your milk jug will never find itself reincarnated as another milk jug. However, where recycling facilities for paperboard milk cartons exist, cartons can be recycled into high-grade paper products. A single milk carton, for instance can be made into five sheets of high-quality copier paper.

From a health perspective, studies have shown that milk exposed to light can lose significant amounts of vitamin A, riboflavin (a type of B vitamin), and vitamin D. Tests in which milk samples in translucent plastic jugs were exposed to dairy-case levels of light showed that more than 50 percent of some vitamins can be lost after just 15 hours. Milk in opaque paperboard cartons is not affected by light and, thus, retains its nutritional value longer. Now, that does a body—and a planet—good.