Health impact of Meat Free Meals

SCIENTISTS WARN AUSTRALIANS OF HEALTH IMPACT OF MEAT-FREE MEALS


Nuts, pulses and seeds can mean short falls in essential nutrients

A new local study, to be published next month, reveals that by simply substituting plant-based for meat-based meals, Australians could be unknowingly cutting out numerous essential nutrients, including vitamin B-12, omega-3 fats, iron and zinc, that aren't readily available from legumes, seeds and nuts.

What's more, the study which analysed a number of different dietary scenarios including meat, poultry and fish as well as plant-based diets (featuring lentils, nuts and seeds) found that in order to absorb the required amounts of essential nutrients from a plant-based meal, Australians would need to substantially increase their portion sizes and kilojoule intake.

The results of the study demonstrate that critical groups in the community - such as menstruating or pregnant women - could fall short of their essential iron, zinc and vitamin B-12 nutrient requirements if they simply replaced meat-based meals by plant-based alternatives on a regular basis. For example, the findings show a meat-based diet provides women with between 125-175 percent of their iron requirements versus 63-111 percent from a plant-based diet. For pregnant women, a meat-based diet provides 86-145 percent of their B-12 requirements versus just 68 percent from a plant-based diet. 

The issue stems from the current Australian Dietary Guidelines grouping together lean red meat, fish, poultry, eggs, nuts and legumes as nutritionally similar foods that provide the distinguishing nutrients iron, zinc and vitamin B-12. Meat, poultry and fish-based meals provide good quantities of vitamin B-12, omega-3 fats, iron and zinc. Legumes, nuts and seeds, on the other hand, do not contain vitamin B-12, important for the normal functioning of the brain, or long-chain omega-3 fats, required for the brain and maintaining a healthy heart. What's more, the iron and zinc content of a plant-based meal is not as easily absorbed by the body as a meat-based one. 

Professor Katrine Baghurst, key author of the study comments: "People need to be aware that they should not simply substitute a portion of a plant-based food for a portion of meat and expect to receive the same nutritional benefits."

Nutrient contribution per serve of the investigated foods is outlined in the table below:

In order to absorb the recommended amounts of essential nutrients, those choosing plant-based meals would need to increase energy intakes due to the additional amounts required. For example, to absorb the required iron and zinc from pine nuts, peanuts and sunflower seeds, 50 percent more kilojoules would need to be consumed.

"Legumes, nuts and seeds undoubtedly provide valuable nutrients and variety should be included in a healthy diet - but our data show they are not direct substitutes for foods of animal origin.  A properly balanced plant-based diet including B-12 and omega-3 fortified foods can provide sufficient nutrients, but if avoiding meat and particularly red meats, altogether, you really need to make sure that you're eating the correct quantities of the right foods to get all the essential nutrients your body needs," says Professor Baghurst.  "Currently the Australian Guide to Healthy Eating does not take these nutritional differences into account sufficiently and this could lead to shortfall in key nutrients in some groups of the community," concludes Professor Baghurst.