Read the passage below. Use the information in the passage and your own
knowledge to answer the questions that follow.
Omega-3
Excess lipids (fats and oils) in the human diet can increase the risk of health
problems such as obesity, heart disease and strokes. However, a balanced diet
needs to contain fats and oils because they are needed in the human body for
many important functions.
5 Scientists have recently discovered that a type of fatty acid contained in oils can
also benefit human health. The fatty acids that provide benefits to human health
are called omega-3 fatty acids. A diet rich in these fatty acids is thought to lower
blood pressure and reduce the risk of heart disease.
Fish oils are known to contain high levels of omega-3 fatty acids. Fish farmers
10 know that the fish they produce are of more value to the consumer if they
contain oils rich in omega-3. As a result, about 80% of the fish oil produced
globally from the oceans is used as food in fish farms.
Small fish called anchovies live in our oceans. They eat microscopic plants called
plankton that contain high levels of omega-3. As the anchovies grow, they also
15 contain high levels of omega-3 in their oil. Fishing boats catch billions of these
small fish, that are then ground up to be fed to bigger fish such as salmon, on fish
farms.
Fish farms consume vast quantities of anchovies. The increase in the number of
fish farms is one reason why wild fish stocks of anchovies are declining. It takes
20 about 5 kg of anchovies to produce 1 kg of farmed salmon. The high cost of this
source of fish oil has encouraged fish farmers to use less, so the fish they produce
contain lower levels of omega-3 in their oil, which is not good for human health.
Recently, scientists have discovered another way to obtain high levels of omega-3
to feed to fish on fish farms. The scientists genetically modified a plant called
25 Camelina to produce seeds containing omega-3 fatty acids. This discovery will
enable these seeds to be fed to salmon in fish farms and could reduce overfishing
of the oceans.