Written by Sebastian Pole
Fat can be healthy, you just have to pick the right ones. We will take you through the good and bad fats, and explain how fat can be incredibly important at maintaining our vitality.
Fat is good for you. That is a fact. The body absolutely requires good quality fat in the diet in order to process such fat-soluble nutrients such as vitamins A, D, E, and K as well as to absorb protective phytochemicals (the colourful flavonoids and carotenoids) and certain minerals. It is essential for creating enough digestive enzymes. We need it to regulate hormone production. It gives us energy. It helps regulate our moods. It protects our organs. It keeps us warm. Our brains are 60% fat. Our nervous system, our brains, our eyes, our joints are all comprised in part from fat.
What type of fat is good for you?
Fats are divided into saturated and un-saturated fats:
Saturated fats are made from short, medium and long chain fatty acids (also known as triglycerides). Short and medium chain fatty acids are easy to digest whereas long chain fatty acids are not. The short and medium chain fatty acids are absorbed in the upper part of the small intestine, not requiring the liver or gall-bladder for digestion and are used immediately for energy. Long chain fatty acids have to go through a much more complex process involving being broken down by bile acids and pancreatic lipase into glycerol and free fatty acids. These are absorbed and then reconstitution into triglycerides which need to be bonded with a lipoprotein before they are transported to a site that can use them. This process takes up to 8 hours before they are stored as fat before becoming energy.
Excessive consumption of long chain fatty acids is associated with blood clotting, thrombosis and cancer. Medium chain fatty acids are known to increase metabolism and promote weight loss. Short chain fatty acids help to promote the production of hormones and strengthening cellular membranes. Ghee is high in short chain fatty acids, whilst coconut oil is high in medium chain fatty acids. Commercial margarines, lard and butter are high in long chain fatty acids.
What is the fad with fat?
Saturated fats have a bad public image as excessive consumption of them has become associated with an increased risk of high cholesterol, atherosclerosis, stroke and coronary heart disease. The Seven Countries Trial which began in the late 1950s, was set up to determine the causes of Coronary Heart Disease (CHD). It associated CHD with saturated fats and this has led to a host of ‘low-fat fads’ and an entire low fat industry. This study is now largely discredited as is the association between saturated fat intake and CHD. Just think what the Eskimos eat…lots of saturated seal and whale blubber. Before westernisation the incidence of CHD amongst traditional Eskimo communities was virtually zero. Another example is Japan, where the rate of saturated fat is increasing but CHD is falling.
The causes of heart disease are much more complex then the ‘fat-heart disease’ hypothesis and involves a balance between the forces of degeneration and the energy of protection including genetic tendency, life-style factors, anti-oxidant status, stress, hostility, hypertension, exercise, sugar metabolism, correct LDL/HDL balance and, of course, dietary factors ensuring sufficient vitamin C, E, soluble fibre, EFAs, flavonoids and carotenoids.
One of the reasons for the controversy regarding the ‘fat-heart disease theory’ is that much research has not differentiated between true saturated fats and synthetically generated saturated transfatty acids. However, this is a misunderstanding of the nature of the saturated fats as some, containing high levels of short and medium chain fatty acids are healthy, such as ghee and coconut oil. Also many of the saturated fats that people eat come from animals raised in intensive farming where they are grain fed. This leads to a reduction in the heart healthy Omega-3 Essential Fatty Acids made available to grass fed animals. This confusion that all ‘fats’ lead to high cholesterol has led people to embrace a ‘low-fat’ diet which may result in low cholesterol. Low cholesterol levels and fat free diets have been associated with depression, and violence. Cholesterol helps us ‘feel good’ as it is an important component of serotonin receptors. Cholesterol also helps us to produce essential hormones such as Vitamin D, oestrogen and adrenaline.
So, saturated fats are important to health, benefiting certain specific metabolic functions, cellular interactions and immune responses. Used at an appropriate quantity and with good quality polyunsaturated essential fatty acids they are beneficial to health. My favourite saturated fats are coconut and ghee as they are easy to digest and have numerous health benefits. (Knopp 2004, Lancet 1992)
Unsaturated fats are divided into monounsaturated fats (olive, mustard) and polyunsaturated fats (sesame, sunflower, flax, corn, hemp). Both are required for healthy life. Polyunsaturated fats (PUFAs) are ‘unstable’ oils. If they are not handled properly they can pose a health risk as their cell structure leaves many ‘bond’ sites that are potential sites for oxidisation to occur. They easily go rancid. Essentially this means that under poor processing and storage conditions (i.e. heat and light) they can become oxidised, a process similar to metals rusting, which allows for the release of free radicals in the body. This leads to accelerated ageing and other degenerative diseases.
Interestingly, sesame oil does not become oxidised under heat as its linoleic acid content actually improves its anti-oxidant status but hemp seed does oxidise easily under heat and light which is why it should not be used for cooking. So, polyunsaturated fats that are handled properly (cold pressed, kept cool, stored away from light) are extremely beneficial for health. If they are not, i.e. when they are processed and stripped of their inherent protective anti-oxidants, then they can create Lipid Oxidation Products (LOPs). As they are toxic to cells, they can damage the lining of the arteries which increases the risk of heart disease and they use up valuable anti-oxidant reserves leaving us exposed to free radical damage. Because of the way they are processed and handled most commercial, non-organic, PUFAs (sunflower, corn etc) contain levels of LOPs and so should never be used for frying as this will create more oxidation. Olive oil as a mono-unsaturated fatty acid contains minimal amounts of LOPs and is safe for cooking. However, no oil should ever be re-used as it will harm your health.
Fats & Carbs: If carbohydrate or fat consumption exceeds your needs then the glucose-like molecules are stored as glycogen reserves for potentially needed energy release in the muscles and liver. If the glycogen bank is full then the overflow gets laid down as fat molecules in the fat cells. As you reduce your dietary intake and/or increase metabolic needs, fat gets converted back to glycogen. As glycogen gets broken down water is also lost in a ratio of 1 part glycogen to 9 parts water. This is why fasting can bring about rapid weight loss but as food is resumed then glycogen levels go back up and an increase in water retention returns.
Calories: Counting calories is one method of monitoring how much ‘energy’ you are putting into yourself. Men require approximately 2,500 calories/day and women 2,000. One pound of fat is created from 4,000 calories. Whilst calorie counting may be useful for raising awareness of the nutritional components of the food you eat it does not consider the individual metabolic rate which is at the crux of all healthy weight diet and life-style regimes.
Glycaemic Index (GI): The Glycaemic Index describes how the body’s sugar levels respond to certain foods. It has become an important indicator of how certain foods will affect weight loss and diabetic control. Foods with a low GI release sugar into the bloodstream slowly whilst those with a high GI can cause a rapid increase. Glucose and refined sugars have the highest GI and whole grains and lentils the lowest.
Insulin resistance: Insulin is the hormone that allows for the absorption of various nutrients including glucose and amino acids and keeps the blood sugar within ‘normal’ limits. Whilst insulin production is stimulated by eating carbohydrates it can also reduce the metabolism of fats and proteins thus leading to greater storage of fats. It is estimated that 8 out of 10 overweight people have a blood sugar imbalance including possible insulin resistance.
The term “insulin resistance” means that your body cells are more resistant to the action of insulin than normal. If you are insulin resistant, your pancreas has to make more insulin to keep your sugar normal. As long as your pancreas can meet the excess demand placed upon it, you are OK. If your pancreas cannot keep up with the increased demand, your blood sugar will rise and you will become diabetic.
Evidence points to an inherited abnormal form of insulin that is inefficient at regulating blood sugar levels. There also appears to be a problem with the insulin receptor not allowing insulin to facilitate the entrance of glucose into the cell.
It is fairly easy to determine whether someone is insulin resistant. One of the most common ways to find out is simply to measure the fasting blood sugar and fasting insulin level in the morning. It is also possible to undergo a Glucose Tolerance Test, measuring both blood sugar levels and insulin levels. If the insulin levels are higher than they ought to be, this indicates insulin resistance.
Insulin resistance is affected by:
- A high GI diet as these foods promote the release of high levels of insulin.
- A high fat diet helps to lower the GI by slowing digestion and delaying the entrance of sugars into the blood stream.
- Excessive insulin secretion creates a negative cycle through over-stimulation. When a cell is exposed to high levels of insulin it starts to alter its relationship with insulin and reduce the number of insulin receptors. This leads to lower levels of fat breakdown and leads to obesity.
- Mineral deficiency in chromium and magnesium (also zinc and B vits).
- Obesity creates insulin resistance and insulin resistance creates obesity.
Insulin resistance leads to ‘hyperinsulinemia’. It is another vicious cycle. As a tissue becomes increasingly insulin resistant, the uptake of blood glucose becomes more inefficient. As a result, blood glucose levels begin to rise and continue to be raised over ever increasing periods of time. The pancreas, in its efforts to effectively store the glucose, responds by secreting progressively higher levels of insulin. When this pattern occurs insulin levels are higher for longer such that the total hours of insulin exposure in the body may be increased to 50-100% beyond that of normal.
Hyperinsulinemia can cause:
- Sodium metabolism disruption, increased water retention and hypertension.
- Oxidative damage and initiation of atherosclerosis and neoplasia (cancer).
- Decrease in the total daily secretion of growth hormone with negative effects throughout the body. One notable effect of this is to inhibit the conversion of the inactive thyroid hormone (T-4) to its active form (T-3). This creates a “functional hypothyroidism,” which is difficult to detect because a routine thyroid blood test will display an otherwise normal level of circulating thyroid hormones.
- Compensatory hypercortisolemia (high blood cortisol levels), poor tolerance to stress, depressed immunity, and eventually, adrenal exhaustion.
- Chronic, high levels of insulin secretion will eventually exhaust the beta cells of the pancreas, increasing the likelihood of a functional deficit of these tissues, resulting in adult-onset diabetes.
A brief word on transfatty acids
The dreaded transfatty acids have become synonymous with poor quality foods and bad health. They are formed when certain polyunsaturated oils are intentionally saturated with hydrogenation under high temperature to make solid fats (an oil is liquid at room temperature and a fat is solid). The technique of creating transfats was developed in the early 1900s in order to extend the shelf-life of unstable fish and vegetable oils. Widespread introduction of transfats into commercial foods began just after the 1920s with disastrous effects. Because of their harmful effects on health the recommendation to remove them from foods is now being legislated around the world.
Transfatty acids are associated with an accumulation of the potentially harmful LDL, the increased risk of heart disease, prostate cancer, diabetes, fertility and liver dysfunction. Transfats are ‘oxidised’ fats and create harmful free radical generating substances called lipid peroxides. Lipid peroxides (oxidised lipids) actually take up residence on cell walls and obstruct the correct working metabolisms of cells. As they interfere with the delta-6-desaturase enzyme conversion of Omega-3 and Omega-6 fatty acids into inflammation modulating prostaglandins they obstruct this crucial protective process.
Transfatty acids can:
- Increase cancer risk factors by disrupting liver detoxification of carcinogens, change B and T immune cell ratios, interfere with the functions of cancer protecting fatty acids
- Elevate cardiovascular risk factors by increasing total cholesterol levels and potentially harmful LDL cholesterol, lowering protective HDL cholesterol, make platelets more likely to stick to together to form a clot, increase the strongest known risk factor for cardiovascular disease (lipoprotein)
- Interfere with insulin function hence increasing the risk of diabetes
- Disrupt fertility by decreasing testosterone and increasing abnormal sperm
- Be associated with low birth weight babies & lower human breast milk quality
- Interfere with essential fatty acids metabolism
- Interfere with nutrient absorption by reducing Vitamin K absorption.
Essential fatty acids
PUFAs contain the fragile Essential Fatty Acids (EFAs) which are found in high concentration in the cells of our brain, nervous system and skin. The cell membranes of the 63 trillion cells we have in us all contain EFAs. There are three types of EFAs;
- Omega-3 fatty acids – including alpha-linolenic acid
- Omega-6 fatty acids – including linoleic acid and gamma-linolenic acid
- Omega-9 fatty acids – including oleic acid
Examples of some Omega containing oils are;
- Fish oil is all Omega-3
- Flax oil is 60% Omega-3 and 20% Omega-6
- Hemp seed oil is 20% Omega-3, 60% Omega-6, 12% Omega-9 oleic acid and 3% GLA totaling more than 90% unsaturated fatty acid.
We need the EFAs Omega 3 to 6 in a certain ratio. The ratio of 1:3 is considered ideal for health (the ratio is debated, but this is the current most accepted figure). This is the ratio that hemp seed has. Flax has the opposite ratio, which can be beneficial for redressing imbalances in the short-term but not for long-term health as it can lead to omega-6 deficiencies. Commonly people have a ratio of 1 to 10 or 20 Omega 3 to 6! This is because animal fats and many commonly used vegetable oils (soy, corn, safflower, peanut and sesame) are high in Omega 6.
Cells that have a rapid evolution, such as those in the skin, immune and nervous systems, and in growing babies and children, need lots of essential fatty acids to stay healthy. It is vitally important that the correct ratio of Omega 3 to 6 is received or imbalances will occur.
Essential fatty acids and health
60% of the weight of our brain, the fat-richest organ in our body, is fat, and one third of that is EFAs. The ratio of omega 3s to omega 6s in the brain is 1:1. EFAs have been shown to help ADHD, Schizophrenic symptoms, Alzheimer’s disease and senile dementia, Parkinson’s, Lou Gehrig’s disease (ALS), and multiple sclerosis.
EFAs help to moisten and nourish the skin preventing dry and flaky skin. As EFAs help form cell membranes they help to keep moisture in the skin and keep cell membrane function at optimum levels. This can positively influence eczema, psoriasis and other inflammatory skin conditions.
EFAs help to reduce Arachidonic Acid levels which can help to reduce menstrual pain. Its mood balancing qualities can also help with PMS.
Pregnant women need a larger intake of EFAs to nourish their child, and this need increases with each extra child. Low EFA levels are also associated with post partum depression and some diseases that have a higher incidence in women; multiple sclerosis, thyroiditis, fibromyalgia and lupus. EFAs also help build male fertility through boosting sperm quality and quantity.
An important function of EFAs is that they make red blood cells more flexible, which means that they can find their way through capillaries more easily. The result is that tissues and cells receive their supply of nutrients and oxygen more effectively, and stamina therefore increases. EFAs also assist in the transport of oxygen and essentially draw oxygen into the cells.
Getting up to 12% of your diet from EFAs can actually help you to loose weight as EFAs help with our metabolism.
EFAs can reduce blood lipid triglycerides by 65% and have been shown to increase HDL and lower LDL in some people. However they are not sufficient on their own to achieve this in everybody and should be used as a part of a cholesterol reducing programme if this is indicated. They also make platelets less sticky which can reduce the chance of blood clots arising.
EFAs are involved in the correct functioning of the DNA and so may help prevent cancers, enhance wound healing and protein metabolism that are so essential for correct immune function. Another important role is that EFAs make hormone-like prostaglandins. There are different forms of prostaglandins, which can either reduce inflammation or be pro-inflammation depending on the source and quality of oil and how it is metabolised in the body. Beneficial prostaglandins (PGE 1 and 3) work to;
- Protect the skin and joints from inflammation
- Reduce cholesterol levels, dilate blood vessels and reduces blood pressure
- Protect integrity of blood vessels and prevent platelet aggregation
- Reduce auto immune inflammation; psoriasis, lupus, crohn’s disease
- Help to reduce menstrual pain
- Reduce the complications of diabetes
- Keep cells functioning properly and reducing cancerous behaviour
If there is not enough Omega-3 in the diet then the prostaglandin metabolites will convert Omega-6 into a pro-inflammatory Arachidonic Acid process. (Simopoulos 1999, Cullis 1991, Grimble 1998, James 2000)
Why are Omega-3 oils so good for our health?
Omega-3 oils are medium chain fatty acids that are metabolised to long-chain eicosapentaenoic acid (EPA) and decosahexaenoic acid (DHA). EPA, is an Omega-3 derived fatty acid that is a precursor to the eicosanoids; prostaglandin-3, leukotrine-5 and thromboxane-5. It is associated with a healthy inflammatory, nervous and emotional balance. DHA is another Omega-3 derived fatty acid associated with brain health, retina health, foetal development and immunity.
Omega-3 deficiency leads to dry skin, growth retardation, weakness, impaired learning ability, poor motor coordination, behavioural changes, impaired vision, high blood pressure, sticky platelets, oedema, mental deterioration, low metabolic rate, and immune dysfunction
What is wrong with Omega-6?
Nothing in itself, it’s just that we have too much of it in our diets. Although Omega-6 is an EFA, and we need a certain amount of it, unfortunately Omega -6 linoleic acids in excess to Omega-3 can create Arachidonic Acid which can cause an inflammatory cascade disrupting the health of the skin, brain, nervous system, fertility, joints and circulatory system. Excess poor quality Omega-6 linoleic acids in our diet are potentially a causative factor in the increase in heart disease in ‘developed countries’ over the last 90 years.
How can we get the perfect balance of Omega-3:6 EFAs?
Some authorities believe that we should be aiming for a 1:1, Omega-3:6 ratio in our diet to redress the imbalances we face from long-term destabilisation in our fatty acid profile. Others recommend a ratio of 1:3. Some suggestions for achieving this are;
- Restrict intake of animal-based foods: meat, dairy, poultry as they are dietary sources of Arachidonic Acid and are precursors to inflammatory PGE2, LTB4, 5-HETE, and 12-HETE.
- Substantially increase dietary sources of omega-3 polyunsaturated fatty acids (PUFAs) ensuring sufficient levels of eicosapentaenoic acid and docosahexaenoic acid that block metabolism of Arachidonic Acid.
- Limit intake of plant-source omega-6 PUFAs, targeting a 1:1 ratio of w3 to w6 PUFAs in severe disease. This helps to prevent enzyme competition and reduce the inadvertent shunt to Arachidonic Acid and inflammatory eicosanoids.
- Increase dietary antioxidants: 7 to 9 servings a day of deeply pigmented fruits and vegetables. This reduces oxidative biosynthesis of inflammatory eicosanoids and isoprostanes.
- Eliminate hydrogenated and trans-fatty acids, alcohol, simple sugars, and refined carbohydrates, and reduce elevated cholesterol levels as these are inhibitors of the desaturase enzyme responsible for converting EFAs to EPA/DHA.
- Ensure adequate intake of zinc, magnesium, ascorbate, niacin, and pyridoxine as these are coenzymes for desaturase metabolism of omega-3 PUFAS.
- Optimize blood glucose regulation: address hyperinsulinemia as excess insulin shifts dihomogammalinolenic acid toward PGE2 synthesis.
- Provide a combination of several anti-inflammatory botanical agents that help to modulate the inflammatory cascade through multiple and synergistic actions, including COX and LOX inhibition.
- Monitor inflammatory markers (e.g., C-reactive protein, ceruloplasmin) at baseline and interval and adjust protocol as required.
Can humans convert Omega 3 ALA into EPA and DHA?
Some authorities (in the fish oil industry?) have said that vegetarian sources of Omega-3 alpha-linolenic acid cannot be efficiently converted into EPA and DHA. However, two studies published in the British Journal of Nutrition which measured the conversion of alpha-linolenic acid (ALA) into EPA, DPA, and DHA have shown otherwise. The first study, carried out with six women, showed that these women converted an average of 36% of the ALA they were given into long-chain Omega-3 derivatives (21% EPA, 6%DPA, 9%DHA).
The second study, done with six men, showed that the men converted an average of 16% of the ALA they received into long-chain Omega-3 derivatives (8%EPA, 8%DPA). In this study, the men produced no DHA. However, another study showed that men convert ALA to DHA as well. It is considered that men can convert 1% of ALA to DHA (Burdge 2002, Emken, Brenna 2002).
It is surmised that women have a better conversion rate as they need to metabolise EPA and DHA for their children as well.
What can influence conversion?
- Too little ALA or Omega-3 intake
- High Omega-6 intake interferes with conversion of Omega-3
- Lack of the vitamins B3, B6 and C and the minerals zinc, calcium, biotin and magnesium necessary for assisting conversion of ALA to EPA and DHA
- Toxic influences
- High carbohydrate diets slow down conversion
- Diets higher in proteins enhance conversion.
- Diets high in saturated or transfats blocks conversion
- Too low a ratio, such as 1 to 10 Omega-3:6 (the average found in Western diets) can lead to symptoms of Omega-3 deficiency. Omega-3 deficiency increases the risk of increasing cardiovascular, immune, autoimmune, diabetic, and inflammatory disease, and leads to sub-optimal intelligence, concentration, mood, and performance. In the two conversion studies published in the BNJ, the diet contained only 1/7th as much Omega-3 as Omega-6. A better ratio would consist of more Omega-3 and less Omega-6 to redress this imbalance.
What is wrong with fish oil?
The global fish stocks are hugely depleted and as it takes 1000Kg of fish to make 1Kg fish oil using fish oil as a health product is not advisable due to the damage it inflicts on our ocean fish stocks. Secondly, our seas are highly polluted. Taking fish oils increases the chance of industrial pollutant toxicity from mercury, dioxins and polychlorinated biphenyls (PCBs). As these toxins tend to accumulate in the fatty parts of fish they are concentrated in the fish oils. They are implicated with a range of diseases from increased aging to neural disorders to cancer.
It is also interesting that the Omega oils and there derivatives ALA and LA are not actually found is fish oils. However EPA and DHA are, but these are metabolised from the ALA and LA found in micro-algae present in the sea. There are all sorts of risks associated with the processing and storage of EPA and DHA due to their tendency to oxidise as they are 5 times less stable than ALA.
So, vegetarian sources are more ethical, more stable and very effective sources of Omega oils.
How much Omega-3 should we have?
The National Institute of Health in the US published a report that on average we should have 3% Omega-6 and 1% Omega-3 and 0.3% EPA and DHA as a total of our calorific diet. Pregnant women are recommended to have 650mg/day of EPA and DHA/ day. Other sources recommend 600mg EPA and 400mg DHA per day.
I am giving the following recommended dose based on the profile in hemp seed oil as it contains the perfect balance of Omega oils.
Women (average weight 50Kg, recommended dose 2-3 tablespoons).
In order to receive the recommended dose of EPA and DHA from a vegetarian source;
- 1 tablespoon per day of hemp seed oil = 9g (9,000mg)
- 9g hemp seed oil has 6.6g LA and 2.2g ALA
The 36% conversion rate of ALA mentioned in the British Journal of Nutrition means that 1 tablespoon hemp seed oil will give you 792mg of long chain Omega-3 with 21% or 166mg EPA, 6% or 48mg DPA and 9% or 71mg DHA.
If you take the recommended 2 tablespoons per day it will give you a total of 1584mg long chain Omega-3s or 388mg EPA, 96mg DPA and 142mg DHA.
Men (average weight 75Kg, recommended dose 3-4 tablespoons per day)
At a conversion rate of 16% ALA to EPA will get 352mg long chain Omega 3s made up of EPA and DPA from 1 tablespoon hemp seed oil. Taking the recommended 3 tablespoons per day will give him 1056mg/day.
This will lead to benefits including lower cardiovascular risk, smoother skin, higher energy levels, better stamina, improved performance and recovery, better insulin sensitivity, lowered cancer risk, lowered inflammation, greater heat production, and improved mood, learning, IQ and calmness, and better ability to handle stress.
Arnesen H N-3 fatty acids and revascularization procedures. Lipids. 2001;36 Suppl:S103-6. Review.
Brenna JT. Efficiency of conversion of alpha-linolenic acid to long chain n-3 fatty acids in man. Curr Opin Clin Nutr Metab Care. 2002 Mar;5(2):127-32.
Burdge G, Conversion of alpha-linolenic acid to eicosapentaenoic, docosapenta-enoic and docosahexaenoic acids in young women. British Journal of Nutrition 2002 Oct;88(4):411-20.
Burdge G , Jones A, Wootton S , Eicosapentaenoic and docosapentaenoic acids are the principal products of alpha-linolenic acid metabolism in young men, British Journal of Nutrition 2002 Oct;88(4):355-63.
Cullis P, Hope MJ. Physical properties and functional roles of lipids in membranes. In:V ance DE, Vance JE, eds. Biochemistry of Lipids, Lipoproteins and Membranes. Amsterdam:Elsevier; 1991.
Emken EA et al Dietary linoleic acid influences desaturation and acylation of deuterium-labelled linoleic and linolenic acids in young adult males. Biochimica et Biophysica Acta 1213, 277-88.
Grimble RF, Tappia PS. Modulation of pro-inflammatory cytokine biology by unsaturated fatty acids. Z Ernahrungswiss. 1998;37 (suppl 1):57-65.
James MJ, Gibson RA, Cleland LG. Dietary polyunsaturated fatty acids and inflammatory mediator production. Am J Clin Nutr. 2000;71(1 suppl):S343-S348.
Knopp R and Retzlaff B,Saturated fat prevents coronary artery disease? An American paradox American Journal of Clinical Nutrition, Vol. 80, No. 5, 1102-1103, November 2004.
Pereira C et al, 2001. The Alpha-Linolenic Acid Content of Green Vegetables Commonly Available in Australia. Int. J. Vitam. Nutr. Res.;71(4):223-228.
Simopoulos AP. Essential fatty acids in health and chronic disease. Am J Clin Nutr. 1999;70(3 suppl):S560-S569.
Storelli MM et al, 2002. Total and Methylmercury Residues in Tuna-Fishfrom the Mediterranean Sea. Food Add. And Contam.;19(8):715-720.
Wallace J, Nutritional and Botanical Modulation of the Inflammatory Cascade—Eicosanoids, Cyclooxygenases, and Lipoxygenases—as an Adjunct in Cancer Therapy, Integrative Cancer Therapies Vol 1, Number 1, 2002.