Course: BIS 105 Environmental Biology

Unit 8 Learning Module

Trends in Food

Trends in Food and Hunger

As discussed in the human population unit, global population is expected to increase to between 9 and 10 billion people by 2050. This will require increases in food production to supply these individuals with their dietary needs. Over the past 50 years, world population has increased by an average of 1.7% per year, while food production outpaced this growth and increased by an average of 2.2% per year. This has resulted in declining rates of the number of people that are food insecure. Food security is the ability to physically and economically obtain sufficient and nutritious food to meet a person's dietary needs. But there are still an estimated 870 million people that suffer chronic hunger.

Malnutrition is the condition that results from a diet in which certain nutrients are lacking, in excess, or an incorrect ratio. The World Health Organization has cited malnutrition as the greatest public health concern. Undernourishment is when an individual does not consume enough calories for growth and maintenance. When individuals do not receive enough protein in their diet it can result in kwashiorkor.

Children and a nurse attendant at a Nigerian orphanage in the late 1960s; children with distended abdomens due to kwashiorkor.

Overnutrition is another form of malnutrition, particularly in many developed nations such as the United States. Obesity results when excess energy is stored as fat and contributes to health problems, such as cardiovascular disease and diabetes, and reduced life expectancy.

U.S. Obesity Prevalence

Biotechnology

Manipulating the DNA of plants (creating genetically modified organisms, or GMOs) has helped to create desirable traits such as disease resistance, herbicide, and pest resistance, better nutritional value, and better shelf life. Plants are the most important source of food for the human population. Farmers developed ways to select for plant varieties with desirable traits long before modern-day biotechnology practices were established. While selective breeding has created many different varieties of crops, there is a limit to what organisms are capable of interbreeding. Modern genetic engineering techniques allow traits from very unrelated species, such as a fish and a strawberry, to be combined in ways that were never possible before.

Transgenic plants have received DNA from other species. Because they contain unique combinations of genes and are not restricted to the laboratory, transgenic plants and other GMOs are monitored by government agencies to ensure that they are fit for human consumption and do not endanger other plant and animal life. Because foreign genes can spread to other species in the environment, particularly in the pollen and seeds of plants, testing is required to ensure ecological stability. Staples like corn, potatoes, and tomatoes were the first crop plants to be genetically engineered.

Transformation of Plants Using Agrobacterium tumefaciens

In plants, tumors caused by the bacterium Agrobacterium tumefaciens occur by transfer of DNA from the bacterium to the plant. The artificial introduction of DNA into plant cells is more challenging than in animal cells because of the thick plant cell wall. Researchers used the natural transfer of DNA from Agrobacterium to a plant host to introduce DNA fragments of their choice into plant hosts. In nature, the disease-causing A. tumefaciens have a set of plasmids that contain genes that integrate into the infected plant cell’s genome. Researchers manipulate the plasmids to carry the desired DNA fragment and insert it into the plant genome.

The Organic Insecticide Bacillus thuringiensis

Bacillus thuringiensis (Bt) is a bacterium that produces protein crystals that are toxic to many insect species that feed on plants. Insects that have eaten Bt toxin stop feeding on the plants within a few hours. After the toxin is activated in the intestines of the insects, death occurs within a couple of days. The crystal toxin genes have been cloned from the bacterium and introduced into plants, therefore allowing plants to produce their own crystal Bt toxin that acts against insects. Bt toxin is safe for the environment and non-toxic to mammals (including humans). As a result, it has been approved for use by organic farmers as a natural insecticide. There is some concern, however, that insects may evolve resistance to the Bt toxin in the same way that bacteria evolve resistance to antibiotics.

FlavrSavr Tomato

The first GM crop to be introduced into the market was the FlavrSavr Tomato produced in 1994. Molecular genetic technology was used to slow down the process of softening and rotting caused by fungal infections, which led to increased shelf life of the GM tomatoes. Additional genetic modification improved the flavor of this tomato. The FlavrSavr tomato did not successfully stay in the market because of problems maintaining and shipping the crop.

Organic Agriculture

Organic agriculture is a form of agriculture that relies on techniques including crop rotation, green manures, compost, and biological pest control. Fertilizers and pesticides can be used, but synthetic versions of fertilizers and pesticides, hormones, and antibiotics are not permitted or heavily restricted. Genetically modified organisms are also not permitted in organic agriculture.

Is organic food more nutritious than conventional food?

The evidence is unclear. Some studies indicate that organically grown fruits and vegetables may have higher vitamin, mineral, and antioxidant levels. However, other studies have found no nutritional difference between food produced using each method. Because most synthetic pesticides are not permitted in organic agriculture, one potential benefit of organic food may be lower pesticide residues on the food. However, there are potentially harmful organic pesticides that are allowed to be used in organic food production such as rotenone.

Below are a list of the foods that often have the highest pesticide use as well as those that pesticide residues are less likely to be a concern.

Dirty Dozen

1. apples

2. celery

3. sweet bell peppers

4. peaches

5. strawberries

6. nectarines (imported)

7. grapes

8. spinach

9. lettuce

10. cucumbers

11. blueberries (domestic)

12. potatoes

Clean Fifteen

1. onions

2. sweet corn

3. pineapple

4. avocado

5. cabbage

6. sweet peas

7. asparagus

8. mangoes

9. eggplant

10. kiwi

11. canteloupe (domestic)

12. sweet potatoes

13. grapfruit

14. watermelon

15. mushrooms

Environmental Benefits

Externalities are typically reduced for organic farming compared to conventionally grown food. Nitrate leaching into waterways, a major cause of dead zones, is 4.4-5.6 times greater for conventional farms than organic farms (Kramer et al. 2006). Biodiversity levels are on average 30% greater on organic plots, although the results can be quite variable (Bengtsston et al. 2005).

Drawbacks of Organic Agriculture

While synthetic pesticides are not permitted in organic agriculture, there are pesticides that are permitted that may be harmful. It is up to individual farmers about their selection of pesticides and the frequency of use. Typically, pesticide levels are lower on organic food.

Since organic farming doesn't allow GMOs, there are potential beneficial varieties that would not be allowed in organic production. Examples include crops that have been modified to increase or add nutritional content of the food. However, the vast majority of GMOs so far have been to add pesticide resistance to crops, not to increase nutrition.

Antibiotics are not allowed for organic livestock. Therefore, an organic cow cannot receive antibiotics to treat an infection. While this has reduced antibiotic use and potentially slowed the development of resistance, it means that livestock that could be easily treated with antibiotics must forgo it since that animal would no longer be able to be labeled as organic.

The Rodale Institute has an ongoing Farming Systems Trial (FST) study that has lasted over 30 years in which they compare organic and conventional agriculture. Their latest report, issued in 2012, concluded the following:

- Organic yields match conventional yields.

- Organic outperforms conventional in years of drought.

- Organic farming systems build rather than deplete soil organic matter, making it a more sustainable system.

- Organic farming uses 45% less energy and is more efficient.

- Conventional systems produce 40% more greenhouse gases.

- Organic farming systems are more profitable than conventional.

As you can see, the issue of the type of food production is a complex issue. Regardless of whether the benefits are real or perceived, organic agriculture has grown rapidly over the past decade.

Cost of Food

Advancements in production, efficiency, and distribution have made food more affordable. In the U.S., the percentage of income that is spent on food has declined 60% over the past 100 years.

In comparison to other countries around the world, Americans spend much less of their income on food.