Hippocrates (460 B.C. - 380 B.C.) is often called the founder of medicine, and he once said "Let food be thy medicine". He was a clever man, because science can now prove that eating the right type of food enhances health. People who often eat fish are more likely to avoid disease, omega-3 is therefore an important part of a healthy diet. The polyunsaturated fatty acids that we call omega-3 are found in meat and dairy, seafood, vegetable oils, nuts and seeds.
Food that is Rich in Omega-3
Meat and Dairy Products
Meat and dairy products may contain omega-3 but the animals must then have been fed fresh grass, something which is not so common today with the demand for high productivity. Cows who eat grain produce more milk, but the milk will contain less omega-3s and other nutrigents. There is for exampel a study (Christa et al.) where different types of cheese were tested. The alpine cheese from grazing cows was much richer in omega-3s than the other types of cheese that were tested. The reason for this is that grass contains lots of omega-3s which is not the case with grain. It makes no difference if the grain is organic or not , since grain is not natural food for grazing animals. Meat from naturally raised animals also contains less saturated fat (Noci et al.).
A study done by Jana Pickova at Sweden's Farming University showed similar results, when the amount of omega-3 in milk was measured. Ecological milk contains more omega-3 because those cows have been given more fresh grass, and this is the reason why the milk is more nutricious. Pickova also says that just because products are ecologically cultivated does not necessarily mean that they contain more omega-3.
Conjugated Linoleic Acid (CLA)
Naturally breeded animals who have eaten fresh grass also has much more conjugated linoleic acid (CLA) in their meat and milk. CLA is a healthy fat that has shown very positive results in animal studies. CLA have shown positive effects against cancer, it lowers the bad cholesterol, reduces arteriosclerosis and reduces the amount of body fat. There are 28 different types of CLA (isomeres) and the most common one in meat is called cis 9 trans 11. However, it is not known whether CLA has any positive effects on humans, but there are a few studies with good results.
Among Finnish women who had breast cancer and had also reached menopause, the researchers have found a relation between cancer and CLA. The women who had cancer also had less CLA in their bodies compared to the control group. One thing that is mentioned in the study is CLA-rich cheese, which may reduce the risk for cancer in postmenopausal women (Aro et al.). Another study where the participants were all overweight, an intake of CLA resulted in a reduction of body fat. For the different groups of participants the reduction was between 0.43 kg and 1.73 kg after twelve weeks. However, the participants did not lose any weight, instead the lean body mass increased as the body fat decreased (Blankson et al.). CLA could also have negative health effects when taken as a syntetically manufactured supplement. In a study of overweight men the insulin resistance increased at the same time as the good cholesterol was reduced, this was for men who were given the isomer trans 10 cis 12 (Riserus et al.).
CLA is a newly discovered fatty acid and there are not many studies available yet. It is therefore difficult for experts and reseachers to come to any conclusions about CLA. However, it seems that natural CLA in food can enhance health whereas CLA supplements may not be as good.
It is well known that fish and other seafood contain lots of omega-3, but farmed fish do not contain omega-3 unless it has been included in their food. Plankton and algae are rich in omega-3 and the natural food for many types of fish.
Oily fish has omega-3 in their flesh and fat. Less oily fish, such as cod, store the omega-3 in the liver. The liver also contains high amounts of vitamine A which is toxic in higher doses. This is the reason why many experts advice against consuming fish oil made from liver.
Fish may also contain contamination and the higher up in the food chain, the more likely it is that the fish is contaminated. This is because bigger fish live longer and therefore has more time to accumulate toxic substances. Sardines and anchovies are good food, according to researcher Andrew Stoll, because they are far down on the food chain, and especially the fish that come from the cold and clean waters in Antarctica.
One may think that farmed fish should be less contaminated than fish from the oceans. However, an American study that measured the contamination in farmed and wild fish from North and South America and Northern Europe, showed something completely different. Farmed salmon contained up to ten times as much contamination compared to wild salmon. Furthermore, the European farmed salmon had higher amounts of contamination than the American (Hites et al.).
Table showing the amount of omega-3 fatty acids in fresh or frozen fish.
Fats and Vegetable Oil
There are many types of fat, some good for your health and others not so good. Fat can be categorized into four groups: cholesterol, saturated, monounsaturated and polyunsaturated fat. Cholesterol is needed in the cells and for some hormones. LDL (low density lipoprotein) is sometimes also called bad cholesterol, and HDL (high density lipoproteins) is the good cholesterol. It is the lipoproteins that transport the cholesterol in the body.
Saturated fat only has single bonds which makes its structure stable, and the fat is solid at room temperature. Too much saturated fat can be bad for your health. Monounsaturated fat is a good fat, it has one double bond and is liquid at room temperature. Olive oil and rapeseed oil contains lots of monounsaturated fat.
The essential fatty acids omega-3 and omega-6 are polyunsaturated. The fish oil EPA and DHA have five and six double bonds, and are therefore liquid even at lower temperatures. Fish oil is heat-sensitive and should be stored in a refrigerator to avoid oxidation. It should therefore not be used for cooking because the heat will destroy the oil.
Another type of fat is trans fatty acids which can be either natural or artificial. Diary products from ruminants naturally contain trans fatty acids, but they can also be artificially created in a lab. This type of artificial fat (hydrogenated fat) is very stable. It is therefore often used in the food industry to prolong the lifespan for preprocessed food. This is considered to be the worst fat of all, and should be avoided if possible. Pastries, ice cream, fried food and preprocessed food often contain hydrogenated fat.
Olive oil, Rapeseed Oil and Flaxseed Oil
Olive oil mainly consists of a monounsaturated fatty acid called oleic acid. It has one double bond at the ninth carbon atom, and is therefore an omega-9 fatty acid. Oleic acid is an important part of the cell membranes and it has antioxidating qualities, which means that it can protect the omega-3 from oxidation. The olive oil that is called "Extra Virgin" is the best one. It is extracted from the olives from the first pressing. It has the highest quality and very low acidity. Another type is "Virgin" oil. It is a cheaper way to extract the oil, the quality is slightly lower and it has a little more acidity. There is no refined oil in "Virgin" and "Extra Virgin" olive oil. Olive oil is suitable for cooking, because it contains lots of monounsaturated fat and very little polyunsaturated fat. This means that olive oil is more heat-resistent than many other types of oil.
|Type of oil||Omega-3||Omega-6||Monounsaturated fat||Saturated fat|
|Olive oil (extra virgin)||1||8||77||14|
|Source: U.S. Department of Agriculture|
Rapeseed oil contains more omega-3 than olive oil. It also contains about 60 percent oleic acid, and only 6 percent saturated fat. It also has a more neutral flavour and color. Cold-pressed rapeseed oil are pressed mechanically, and three drops per second are extracted, this according to the Swedish Rapeseed Corporation. The temperature is no higher than 40-45 degrees Celsius.
Flaxseed oil is the oil that contains the most omega-3, and it is therefore very heat-sensitive. Don't use it for cooking and store it in the refrigerator to avoid oxidation.