What Vegetables Have Nitrates?

What Vegetables Have Nitrates?

Overview

Nitrate is a type of naturally occurring inorganic ion, or electrically charged molecule, that contains one atom of positively charged nitrogen and three atoms of negatively charged oxygen. Although largely inessential to the operation of the human body, you nevertheless most likely ingest nitrate every single day. Vegetablesare a source of nitrates in the diet.

Nitrogen Cycle

Nitrate is a natural part of the nitrogen cycle, the process by which nitrogen is cycled through the environment in its various chemical forms. Nitrogen is a fundamental part of organic molecules such as proteins. Once it is recycled, this nitrogen returns back to the earth. Microbes that live in soil or water decompose wastes full of nitrogen into ammonia and then metabolize it further into nitrite and nitrate. It can then migrate into plants that make use of soil and groundwater. In fact, nitrate is an important part of plant nutrition.

Vegetable Sources

According to the Agency for Toxic Substances and Disease Registry, vegetables account for more than 70 percent of the nitrate in a typical human diet. However, the leaves and roots of plants tend to contain the highest concentrations of nitrate, where it is absorbed from the soil and then subjected to the effects of photosynthesis. This means that the greatest exposure to nitrate occurs from the consumption of leafy green vegetables such as cauliflower, spinach, collard greens, lettuce, spinach and broccoli. The other parts of plants contain palpable but lesser amounts of nitrate.

Effects

Even in large amounts, nitrate is relatively benign in most adult humans. It tends to be absorbed and then excreted through urine, which is the fate of most nitrogen-based molecules. In the blood, however, nitrate has the effect of converting hemoglobin, the oxygen-carrying blood cells, into a molecule known as methemoglobin that is inefficient at transporting oxygen. This can result in a reduced oxygen supply to tissue such as the brain in infants and people lacking certain enzymes whose bodies cannot convert methemoglobin back to hemoglobin unlike in most healthy adults. This can also occur in pregnant women and adults with weak stomach acidity. Symptoms include headaches, dizziness, weakness and difficulty breathing.

Recommended Intake

Vegetables are only rarely a source of acute toxicity. The European Food Safety Authority, a regulatory and risk assessment branch of the European Union, found that an individual eating the recommended intake of vegetables, even when accounting for the intake from water and other food sources, receives a median dietary exposure to nitrate of 157 mg per day. By comparison, an adult weighing 60 kg, or 132 lbs., would have an acceptable daily nitrate intake of 222 mg per day. The researchers found that leafy vegetables were the critical driver behind exposure to nitrate.

source : livestronge.com