As protective as fruits and vegetables may be, however, eating the right fats may be even more effective in fighting cancer. It might be possible for omega-3 fatty acids to make chemotherapy more effective and also reduce the toxic effects of chemotherapy based on findings obtained from clinical studies in animals.

As a rule, fats high in omega-6 fatty acids promote malignant growth while fats high in omega-3 fatty acids block it. Their effects on cancer are summarised in the following table :

Effect on Cancer	Omega-6 Fatty Acids	Omega-3 Fatty Acids
Growth rate of pre-cancerous cells	Enhances	Inhibits
Initiation of new tumours	Enhances	Inhibits
Rate of tumour growth	Enhances	Inhibits
Spread of tumours	Enhances	inhibits

Omega-3 fatty acids are important nutrients that are involved in many human biological processes. The body cannot make these chemicals and must obtain them from dietary sources or from supplements. Omega-3 family comprises three fatty acids namely :

• Alpha-linolenic acid
• Eicosapentaenoic acid
• Docosahexaenoic acid

Clinical studies on animals have shown that omega-3 fatty acids may offer some protection against cancer, heart disease, arthritis and kidney failure.

People who take anticoagulant drugs or aspirin should not consume additional amounts of omega-3 fatty acids due to the risk of excessive bleeding.

In 1990 the National Cancer Institute (NCI) launched a program to learn more about biologically active plant chemicals, phytochemicals, in certain foods that may help to prevent cancer. Flaxseed was the first of six foods to be studied. Preliminary results indicate that flaxseed oil can exert powerful anticancer properties if the oil is high in lignan precursors based on clinical studies on animals.

Lignans can act as antiestrogens or as weak estrogens, which may play a role in preventing estrogen-dependent cancers such as breast cancer and other cancers. Lignans may also function as antioxidants and may slow cell growth by mechanisms not yet understood. When flaxseeds are consumed, the lignans are chemically converted into active forms by bacteria in the intestine.

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When flaxseed is rough-ground, it will spoil rapidly within 10-15 minutes. So far, honey is the best preservative for rough-ground flaxseeds. Eating whole flax seed is a waste of money because the body cannot extract its goodness. Most of the whole seeds cannot be digested and are simply passed through the body and then excreted.

Some possible side effects include diarrhea, gas and nausea. It should not be used with other laxatives or stool softeners.

People who have inflammatory disease of the intestine, esophagus or stomach should avoid flaxseed.

The immature pods of flaxseed are poisonous.

Flaxseeds contain a chemical called thiocyanate (SCN). If you have high amounts of SCN in your blood for long periods of time, it can keep your thyroid gland from taking up enough iodine, increasing your risk of goiter. However flaxseed oil does not contain cyanogen.

People who have gallbladder problems, such as gallstones may have trouble digesting flaxseed oil.

To truly realize the potential flaxseed oil has on human health, you must choose a product that has been manufactured and handled under very stringent conditions in order to protect the oil from degradation.

Obtaining high-quality flaxseed oil is a major challenge for consumers. The below are some shopping tips when buying flaxseed oil :

• Its taste varies greatly from brand to brand. Brands that many people prefer are Omega Nutrition and Barlean's because they have a milder, nuttier flavour than others. Fresh flaxseed oil has a characteristic nutty flavour and if it goes rancid, you can tell at once by the smell. So as soon as you open a new bottle, give it a sniff to make sure the oil is fresh.
  
  
• It spoils more readily than all other oils due to its high omega-3 content. Therefore it must always be stored in the refrigerator.
  
  
• Some brands such as Barlean's come with special labels telling you the date the oil was pressed and its expiry date.
  
  
• Look for oil with lignans. Lignans are a class of highly researched plant chemicals that have been found to have anticancer, antifungal, antibacterial, and antiviral properties. Their greatest attribute is in the possible prevention of breast and colon cancers. The highest concentration of lignans is found in the hull of flaxseeds. Generally, flaxseed oil does not contain lignans because the fragmented hull settles out of the oil during processing. The exception to the rule is a "High in Lignan" flaxseed oil product marketed by Barlean's Organic Oils, where the fine flaxseed hull particulate has been retained in the oil.
  
  
• Look for oil that is made from organically grown flaxseed to ensure that it is not tainted with pesticides.
  
  
• It has a natural shelf life unless they have been artificially pressed to increase their longevity.
  
  
• It is certified as organic by a reputable third party source indicated on label or promotional materials.
  
  
• Products contained in opaque (light-resistant) plastic containers.
  
  
• Products recommended by reputable health and nutrition authorities. Barlean's Organic Flaxseed Oil is recommended by Dr Johanna Budwig.