With the world’s population predicted to grow from 7 billion to 9 billion people in the next 35 years, it has been suggested that animal agriculture is becoming a wasteful luxury. Do we need to eliminate meat, milk and egg production and grow human food instead of animal feeds?

A group known as the Council for Agricultural Science and Technology has attempted to look at the current situation and to use some known facts to answer the "feed or food" question.

QUESTION: Could we feed more people in the future if we got rid of animal agriculture?

ANSWER: The simple answer is no. The more involved answer is that it depends on the natural resources and environmental conditions available in various parts of the world.

The Food and Agriculture Organization estimates that 70 percent of the world’s agricultural land area is covered by grasslands. Most of these areas could not be converted to production of human plant foods due to limitations in resources like water availability and climate.

Fortunately, these areas can be utilized by our ruminant friends such as cows, sheep and goats. They can eat and digest things like grass that we cannot.

These animals don’t just thrive on grains and soybeans that could be fed to humans. They also consume many food production byproducts such as the residue from vegetable oil production or the milling of grains. There are many other examples of things like this that would not be utilized for food production if it were not for animal agriculture.

For land where human-consumable plant foods can be grown, we may need to balance the environmental constraints with what can be grown. Sometimes the most productive crop may be an animal feed crop like alfalfa. Humans can digest alfalfa sprouts, but not the mature plant that is an excellent feed for cattle.

Q: What are realistic goals for agriculture as we grow into more challenging times?

A: At the top of our list of concerns must be having the capacity to meet the essential nutrient needs of all people. Second, we must find ways to do this in a sustainable fashion that preserves our land, resources, and the natural environment.

This is no small task and will require ongoing growth in our knowledge of the complex factors involved in food production around the world and the ramifications of food production decisions.

Q: What nutrients are of greatest concern for meeting future human needs?

A: Human life is not possible without an adequate supply of essential nutrients — vitamins, minerals, water and key components of proteins and fats. Potentially beneficial but nonessential phytochemicals are health-promoting components in the diet, but they have no real value if even one essential nutrient is lacking.

Currently, key nutrients in short supply worldwide include protein, iron, vitamin A and iodine, to mention a few. People who get their protein from plant food sources need to consume more protein to make up for the lower digestibility and amounts of essential amino acids.

Iron presents a similar issue. The Institute of Medicine estimates that someone consuming a vegetarian diet needs to consume almost twice as much iron as someone who includes red meat in his or her diet.

Food systems that meet human nutrient needs are extremely complex, requiring input from multiple disciplines. Without this teamwork, humans may soon be added to the endangered species list.

Alan Titchenal, Ph.D., C.N.S., and Joannie Dobbs, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.