As far as supplements go, the benefits of cod liver oil make it one of the most worthwhile to invest in. It can improve your skin, digestion, bone health, and even your mental health!
However, here at OriGym we recognise that there is often confusion and concern in regards to cod liver oil; does cod liver oil work? What are the side effects? Is it possible to overdose?
We’ve answered all of these questions and more in this comprehensive guide, so read on to find out the benefits of cod liver oil and why you should be taking it.
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In this guide we’re going to detail the following subjects:
- What is Cod Liver Oil?
- 9 Benefits of Cod Liver Oil
- Cod Liver Oil Side Effects
- Cod Liver Oil Dosage
- When To Take Cod Liver Oil
- How To Take Cod Liver Oil
- Difference Between Cod Liver Oil and Omega-3
- Where To Buy Cod Liver Oil
- Fitness Associations Of Cod Liver Oil
What is cod liver oil?
If you're considering fish oil supplements, it's reasonable to wonder, ‘where does cod liver oil come from?’.
The answer is simple. Fish oil is extracted from the livers of cod (predominantly Atlantic and Pacific varieties). Cod liver oil is one of the oldest supplements in the world, and it's been in use since 1789.
More specifically, it’s packed to bursting with omega-3 and the healthy acids eicosapentaenoic (EPA) and docosahexaenoic (DHA), as well as large amounts of Vitamin A and D. Cod get these high levels of omega-3 from their diets of phytoplankton, a type of microscopic underwater plant, which contain microalgae: the source of omega-3.
High quantities of the latter mean that cod liver oil is frequently used to treat those suffering from a Vitamin D deficiency, and was a common remedy for rickets. It’s one of the more well-known supplements and was often given to children in schools.
Many people wonder ‘what is cod liver oil good for?’, and the answer is many things!
Cod liver oil supplements are popular amongst a range of different people for their benefits on the skin, digestion, joints and much more. Longer term benefits even include lower cholesterol and improved heart health.
Cod liver oil uses are broad and varied, and it's one of the most popular supplements around. It's also one of the safest supplements, so you’re able to give it a try without worrying too much about nasty side effects.
It comes in various grades, and can be taken either as a liquid or in capsule form. The latter is much more popular, since the oil is renowned for its pungent taste!
The many benefits of cod liver oil have always outweighed the taste, but capsules take that out of the equation altogether.
What are the benefits of cod liver oil?
#1 - Great for Heart Health
One of the most important health benefits of cod liver oil is how it helps the heart.
There are quite a few reasons for this, not least that cod liver oil can help to reduce cholesterol and blood pressure. It does this in a few different ways.
The high levels of omega-3 in cod liver oil help to reduce the amount of triglycerides in the blood - triglycerides being a type of fat that contribute to high cholesterol levels in the body.
Additionally, omega-3 promotes an increase in good, healthy cholesterols such as lipoprotein. High cholesterol is a major risk factor in heart disease, and bringing it under control is one of the first steps that a doctor will recommend for better health and reduced risks of deterioration.
Better still, cod liver oil has been shown to reduce blood pressure too. This is once again due to fatty acids of omega-3, which help to prevent blood clots forming, another big danger for heart disease.
Another risk factor in heart disease is from vitamin D deficiency. This can lead to Metabolic Syndrome, the consequences of which include high glucose, blood pressure and cholesterol levels.
All of these factors have a negative outlook for the heart. Cod liver oil remains one of the best and most popular treatments for Vitamin D deficiency, so it’s a brilliant way to treat Metabolic Syndrome in those who aren’t getting enough of the all-important vitamin. Over 1 billion people are thought to be Vitamin D deficient, and it’s possible to suffer from this deficiency without knowing.
Whether you choose liquid cod liver oil or opt for the tasteless capsule/tablet form, the heart benefits remain the same. Decreased cholesterol, lower blood pressure and less risk of blood clots are fantastic reasons to choose the supplement.
Interestingly, preliminary studies have also linked cod liver oil to helping with arrhythmia (irregular heartbeat) too.
If you're looking for another healthy product that can improve your heart health (along with other benefits), take a look at our guide on green tea where we walk you through everything you need to know about this popular substitute for tea and coffee.
#2 - Improves Bone and Joint Health
Many people hear about the health benefits of cod liver oil and wonder; ‘does cod liver oil help joints?’. The answer is a resounding yes!
In fact, improved bone and joint health are some of the leading reasons that individuals choose these supplements. Cod liver oil was originally given to children in schools to help with bone development and to treat conditions such as rickets in poorer communities.
These bone benefits are linked to the cod liver oil vitamin D content. The oil is rich in Vitamin D, which has been shown to slow down the process of bone loss and breakdown.
Better still, studies suggest that those who take a regular supplement of cod liver oil are less at risk from bone fractures. Cod liver oil boosts bone mineralization, too. This is discussed in the journal, American Institute of Nutrition:
“There are several studies that demonstrated an increase in calcium intake of 800-1000 mg/d with supplementation of >400-800 units of vitamin D daily will decrease the risk of vertebral and nonvertebral fractures and increase bone mineral density. ” (Holick, 1996)
There have been plenty of academic studies into the effects of cod liver oil on joint health. There is evidence to show that fish oil can decrease morning stiffness, soothe painful or swollen joints, and even decrease pain intensity within joints.
If you're particularly concerned with your joints and muscles after working out then perhaps one of the best BCAA supplements would be more beneficial!
Taking cod liver oil for joints can benefit everybody, but those benefits are especially pronounced for anyone suffering from bone or joint diseases, such as rheumatoid arthritis.
One study showed that two teaspoons of cod liver oil taken daily actually decreased a rheumatoid arthritis patient’s reliance on NSAIDs (non-steroidal anti-inflammatory drugs).
Anti-inflammatory drugs come with a range of side effects, so being able to decrease the dosage through cod liver oil supplements is a huge benefit. The study was small and there’s certainly more research to be done in this area, but initial results are promising.
#3 - Boosts Skin Health
For those who take cod liver oil, acne and skin problems are often a motivating factor.
Supplements can help, and cod liver oil has wide ranging benefits for the skin. The oil isn’t just rich in Vitamin D, but Vitamin A too, and the fatty acid omega-3 is essential to all body health, but particularly important for the skin.
A single teaspoon of cod liver oil contains an impressive 850-4,000 IU of Vitamin A, which is brilliant news since Vitamin A can’t be produced naturally in the body.
With cod liver oil tablets, benefits include healthier looking skin and a reduction in acne and eczema symptoms. Cod liver oil benefits skin because it contains what we might term “good” fats that promote mineral and vitamin absorption.
Many people ask ‘is cod liver oil good for skin?’, and the answer is simple.
Yes - this supplement contains some of the most important compounds for clear and healthy skin.
Another great supplement that can help your skin is milk thistle: check out our milk thistle benefits, side effects and uses guide here to find out how it can benefit you!
Even more specifically, there are plenty of reasons to choose a cod liver oil eczema remedy. Not only do Vitamins A and D have some huge benefits for the skin, but once again the fatty acid omega-3 is incredibly important.
Controlled studies in hospitals showed that patients with severe eczema experienced a dramatic improvement in their symptoms when supplemented with fish liver oil.
Omega-3 is a powerful anti-inflammatory, and there’s even evidence to suggest that cod liver oil supplements can stop infants developing eczema in the first place.
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#4 - Rich in Vitamin A
Vitamin A is important because it’s classed as an essential micronutrient, which means that, while it’s crucial for human health, the body can’t produce it naturally. It’s important for a number of functions in the body, clearly discussed in this extract from the academic journal Community Eye Health:
“Vitamin A is essential for many physiological processes, including maintaining the integrity and function of all surface tissues (epithelia): for example, the skin, the lining of the respiratory tract, the gut, the bladder, the inner ear and the eye. Vitamin A supports the daily replacement of skin cells and ensures that tissues such as the conjunctiva are able to produce mucous and provide a barrier to infection. Vitamin A is also essential for vision under conditions of poor lighting, for maintaining a healthy immune system, for growth and development and for reproduction.” (Gilbert, 2013)
This high vitamin content is the main difference between cod liver oil and omega-3 supplements. The latter is useful, but the extra hit of Vitamin A contained in cod liver oil makes it superior.
Many of the health benefits of cod liver oil are derived from Vitamin A. Studies have shown that it helps to develop a strong immune system, which is why cod liver oil for kids is such a popular choice.
Vitamin A deficiency makes people much more vulnerable to diseases, especially childhood illnesses like measles, as well as other health issues such as dry skin and night blindness.
Studies have also shown that those who lack Vitamin A are more prone to fractures and broken bones. While Vitamin D and calcium are the main components of bone growth, Vitamin A is essential for the maintenance of healthy bones.
Again, that’s why cod liver oil for children is such a popular option, and why the supplement was often given out in schools.
Other benefits of Vitamin A include reduced risk of acne and eczema, protection from night blindness and generally better eyesight. There’s even some evidence to suggest that Vitamin A can offer some protection from certain cancers.
However, all of this comes with a caveat. It is possible to consume too much Vitamin A.
It’s fat soluble, so it can build up in the body, which is one of the main cod liver oil side effects. Taking too much can cause problems, and a cod liver oil overdose can lead to dizziness, nausea and headaches, all linked to excess Vitamin A.
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#5 - Strong Anti-Inflammatory Properties
Perhaps the single biggest benefit of cod liver oil is its highly praised anti-inflammatory effect. The majority of cod liver oil nutrition comes from the fatty acid omega-3, which is thought to be responsible for the anti-inflammatory response.
Omega-3 is present in all fish oils, but, as we discussed before, the addition of Vitamins A and D are likely to compound the effect and further bolster cod liver oil’s anti-inflammatory credentials.
A common question ‘what does cod liver oil do?’, and the answer is linked to how it reduces inflammation throughout the body. Most of the supplement's more pronounced effects involve reducing inflammation and accompanying pain, which is why cod liver oil is taken for pain relief, digestive health and even as part of the recovery process post workout.
Moreover, reducing inflammation has a knock on effect for reducing anxiety and generally supports things like liver health.
Inflammation is a major risk factor in many diseases, and that’s why cod liver oil supplements are, albeit tentatively, linked to protection from certain cancers, with a small number of scholastic articles, such as The Anticancer Effects Of Vitamin D And Omega-3 Pufas In Combination Via Cod-liver Oil: One Plus One May Equal More Than Two by Martin C.Dyck, David W.L. Ma, and Kelly Anne Meckling, discussing its role as a potential anticancer agent.
Did you know that the benefits of blueberries also include strong anti-inflammatory and antioxidant properties, and more?!
This supplement is a safe way to relieve pain and lower inflammation, but there are a few things to bear in mind: the cod liver oil capsules side effects are usually caused by exceeding the daily recommended dose, especially since it is possible to overdose on Vitamin A.
We’ll discuss the potential side effects later on.
#6 - Brilliant for Digestive Health
When people ask ‘is cod liver oil good for you?’ they’re usually searching for immediate, tangible effects.
While the long term benefits of taking the supplement are clear, some of them (such as healthier skin and hair) do take a little longer to reveal themselves.
Cod liver oil’s effects on digestion are much more immediate though, and the supplement can have some profound benefits for those suffering from digestive complaints.
Fish oil is generally great for digestion. Studies suggest that it can ease the debilitating symptoms of Crohn’s Disease and even Ulcerative Colitis. Once again, this is attributed to the supplement’s high omega-3 content. The effects are discussed in the journal Nutrition Reviews, which states:
“Fish oil has been observed to have anti-inflammatory effects; although it is not entirely clear how these effects are achieved, fish oil modulates inflammatory mediators that are considered to be operative in CD [Crohn’s Disease].” (Kim, 1996)
Fatty acids are crucial to a number of bodily functions, and digestion is no exception. The best cod liver oil supplements will contain large amounts of omega-3, which has the dual effect of soothing the stomach and helping your body to ingest more vitamins and minerals from other foods.
Similarly, cod liver oil is a popular treatment for constipation. Omega-3 is the main player here, too. By easing indigestion and helping the body process food more effectively, a cod liver oil constipation remedy will help with regular bowel movements.
For another natural way to improve digestion, incorporate eggplant into your diet!
Pure, organic cod liver oil is an effective choice for digestive health as it’s free from additives and manufactured using simple processes. However, it’s always advisable to work out your cod liver oil dosage before taking any so potential adverse side effects are avoided. Adults should always read the label carefully and follow instructions.
If you’re searching for a good cod liver oil alternative that yields a similar effect, any fish oil will suffice. A high omega-3 content can be found in any such oil, but those substitutes won’t contain Vitamins A and D.
However, if you’re after a supplement purely for digestive health, then that isn’t too much of an issue.
#7 - Improves Eye Health
Cod liver oil benefits the eyes in a number of interesting ways.
There’s increasing evidence to suggest that cod liver oil is effective at treating both of these problems. One study states that:
“Many natural compounds have been found beneficial for glaucoma. Nutritional therapies are now emerging as potentially effective in glaucomatous therapy. One nutritional supplement with potential therapeutic value is cod liver oil, a dietary supplement that contains vitamin A and omega-3 polyunsaturated fatty acids (PUFAs). Vitamin A is important for preserving normal vision and it is a well-known antioxidant that prevents the oxidative damage that contributes to the etiology and progression of glaucoma.” (Huang, Fan and Zhang, 2011)
Once again, it’s the combination of fatty omega-3 acids and Vitamin A that are behind the health-boosting effect.
Omega-3 helps to reduce degeneration associated with inflammation, something which has been borne out by studies on both animals and humans. One animal based study found that supplementation with omega-3 reduced nerve damage in the eye as well as pressure, and decreased the risk factors for glaucoma.
A wider ranging and human based study yielded similarly positive results. It found that individuals who consumed more omega-3 were 38% less likely to suffer from late AMD (age-related macular degeneration) and more generally a less risk of early AMD as well.
These results are extremely encouraging, and seem to suggest that the answer to ‘does cod liver oil work for eye health?’ is a resounding yes!
Moreover, studies have generally shown that Vitamin A rich diets are great for lowering your risk of developing glaucoma and maintaining healthy eyes. Omega-3 is also thought to help with dry eyes by replenishing the natural oil film on the edge of the eyelid.
#8 - Can Alleviate Anxiety and Depression
There’s increasing evidence to suggest that cod liver oil supplements can really help people suffering from depression, anxiety or some combination of the two.
These results are attached to one of the largest studies on the list, involving a staggering 21,835 people. It found that individuals who took cod liver oil supplements suffered from the symptoms of anxiety and depression far less; 2.5% of those taking cod liver oil showed depressive symptoms compared to 3.8% of those who didn’t.
It might seem surprising that something as simple as fish oil can have such a profound effect on mental health, but there are some suggestions as to why this might be the case.
The anti-inflammatory properties of omega-3 could play a part. If you’re wondering how this works, then a little scientific background from the journal Brain, Behaviour, and Immunity will help:
“Both depression and anxiety can enhance the production of proinflammatory cytokines. Inflammatory mechanisms have been implicated in the pathophysiology of depression, and stressful experiences that sometimes precipitate depression can also boost proinflammatory cytokine production. The n-3 PUFA’s [omega-3] antidepressant properties may be related to its ability to dampen inflammatory responses.” (Kiecolt-Glaser et al., 2011)
By reducing inflammation, omega-3 might also reduce anxiety and depression. Similarly, reduced symptoms of depression have been linked to a higher concentration of Vitamin D in the blood.
Fatty acids are vital to healthy brain function, especially the omega-3 acids EPA and DHA, so much so that studies suggest higher levels of DHA are linked to larger brains and increased cognitive function.
The acids are found throughout the brain, most notably in cell membranes, where they play a vital role in communication between brain cells.
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#9 - Aid Respiratory Diseases and Lung Health
Another fantastic benefit to cod liver oil is that its anti-inflammatory properties can help those suffering from respiratory problems like asthma or chest infections.
The reasons for this are fairly straightforward. Cod liver oil supplements can be used to reduce inflammation in the lungs and chest, as well as throughout the body.
This is due to both the high omega-3 content and the additionally beneficial vitamin D. The effects of this are discussed in Respiratory Research:
“Several lung diseases, all inflammatory in nature, may be related to activities of VitD [vitamin D] including asthma, COPD and cancer. The exact mechanisms underlying these data are unknown, however, VitD appears to impact on the function of inflammatory and structural cells, including dendritic cells, lymphocytes, monocytes, and epithelial cells.” (Herr et al., 2011)
Since these effects are induced due to the anti-inflammatory properties of omega-3, fermented cod liver oil might be a better option. Proponents claim that the fermented variant of cod liver oil contains more antioxidants, which in turn means that omega-3 is preserved better over time.
Fermented cod liver oil benefits those in search of a higher omega-3 content, and is, therefore, a good choice if you’re focussed on boosting your respiratory health.
Cod Liver Oil Side Effects
As with the majority of supplements, even cod liver oil has certain side effects and risks involved. It is generally considered safe to take daily.
However, side effects can undercut the benefits if you take too much cod liver oil, and they can include:
- Heartburn/Acid Reflux
- Nosebleeds/blood thinning
- Low blood pressure
- Not always recommended during pregnancy.
Remember that these side effects usually only occur when cod liver oil is taken in high doses (read on to our chapter on cod liver oil dosage to find out how much is recommended daily).
It’s worth taking into consideration that the cod liver oil tablets' side effects include digestive discomfort and nausea if you take too many, so if you already suffer from related conditions be sure to double check dosage and be sure not to take too much cod liver oil.
If you find yourself experiencing stomach discomfort after taking cod liver oil then take it with or before food, as this will help you digest the omega-3 better!
Additionally, high strength cod liver oil is particularly linked to these side effects, which are caused by an excess of fat soluble Vitamin A.
Cod Liver Oil Dosage
An important question that you should consider before investing in fish oil is “how much cod liver oil per day?”. You need to know the correct dosage in order to avoid any potential side effects.
Currently there aren’t any standardised recommendations for daily cod liver oil (or fish oil) intake, instead the recommended dosages are based on overall omega-3 consumption, which includes EPA and DHA (which we discussed earlier).
It’s recommended that a minimum of 500mg of EPA and DHA (omega-3) is consumed daily, with a more appropriate amount being around 3000mg-4000mg for adults, while it’s stated that omega-3 is safe for adults in daily doses up to 5000mg. This amount should be considered when looking at the daily cod liver oil dosage for adults.
It is important to note however, that the amount of omega-3 needed varies for each individual, and a number of variables contribute to how much you should be taking, including:
- Underlying health conditions
Your individual needs should be taken into account when attempting to calculate necessary omega-3 doses.
That being said, how much cod liver oil per day is slightly easier to work out as all supplements will have clear instructions and dosages stated on the packaging. These will be generally safe and efficient amounts, so following the instructions will suit the majority of consumers. This also means that as long as you follow these guidelines then the chance of a cod liver oil overdose is incredibly slim.
Whilst cod liver oil comes in both capsule and liquid form, the standard dosage is the same.
Another key factor to note when taking cod liver oil capsules or liquid, is that cod liver oil also contains vitamins A and D, whereas other fish oil does not. The recommended daily amount of vitamin A is around 1.5mg, and it is important not to exceed this as too much vitamin A can have some bad side effects.
When To Take Cod Liver Oil Capsules: Morning Or Night?
Many people wonder when to take cod liver oil capsules (and liquid) but the truth is that the time of day makes little difference. There’s not really any set best time to take cod liver oil, rather the effect of the supplement is compounded over time when taken daily.
The health benefits of cod liver oil are linked to long term use rather than one off doses, so taking supplements at any time of day will have the same effect. That said, it can be useful to take it with meals (this will help reduce any stomach discomfort).
The question of “how long does cod liver oil take to work?” is nuanced and unique to each individual, but the benefits won’t come overnight. The aim is to take the supplement regularly, and the effects are long term rather than immediate.
How To Take Cod Liver Oil
Cod liver oil supplements come in either liquid or capsule form. Capsules are immediately easier to take due to the lack of the fishy taste and smell, but these can sometimes be more expensive. The size of the capsules can sometimes be on the larger side too.
The dosage for cod liver oil tablets or capsules is usually one a day, but of course, check the specific brand’s instructions to ensure you’re taking the correct amount. Swallow the capsule whole, and follow with some water to help ease the tablet down.
Liquid cod liver oil comes with a few caveats. Obviously, the liquid form comes with a fishy taste and smell; however, investing in higher quality and fresher liquid will mean that the fish taste won’t be overpowering or even that unpleasant. If you find that the taste is particularly bad, or even rancid, then your liquid cod liver oil could be past it’s use by date!
There are few ways that you can take liquid supplements:
- Plain, straight from a teaspoon - probably not recommended for those that don’t like fish!
- Mixed into a glass of water - this will help dilute the taste, just be sure to drink it fast and drink it all!
- Mixed with a small amount of an acidic drink, such as juice - the slight acidity of juice will mix well with the oil. Be sure to choose something with a strong enough taste to cover the fish oil, for example orange juice.
- Take straight from the teaspoon and follow with a slice of fruit, such as lemon, orange, or even a slice of cucumber - the freshness of the fruit (or veg!) will help quickly cleanse the fish taste from your palate.
Difference Between Cod Liver Oil And Omega-3
Many people often use cod liver oil and omega-3 interchangeably: whilst they are closely related, they are not the same thing!
Omega-3s are essential fatty acids that are necessitated by a huge number of parts of the body. The body doesn’t produce these by itself, which means we get all omega-3 from our diet.
There are 3 main types of omega-3s:
- Alpha-linolenic acid (ALA) - this is the most common, but the conversion process of ALAs into the more effective EPA and DHA within the body is inefficient. The body uses ALAs for energy, and it is found in foods such as seeds and nuts.
- Eicosapentaenoic acid (EPA) - this acid can also be converted into DHA.
- Docosahexaenoic acid (DHA) - this is the most important acid out of this group as it is a crucial structural element of many parts of the body, including the eyes and the brain. These are found in some fish and dairy products.
Cod liver oil is actually a supplement that contains these acids, but isn’t the same as omega-3s.
Where To Buy Cod Liver Oil
Cod liver oil supplements are very common which means they are readily available from a lot of retailers, including most supermarkets which stock their own brand supplements at a cheaper price.
Additionally there is always the option of buying online from places such as Amazon UK, who will supply a much wider variety of cod liver oil products.
Fitness Goals Assisted by Cod Liver Oil
If you’re specifically wondering how cod liver oil could help you in the gym or help your sports performance then there are a few ways that it does this, including:
#1 - Increased Strength And Muscle Mass
Its anti-inflammatory properties means it’s good for aiding muscle recovery as it will reduce the inflammation of muscle cells which occurs after working out. This means you can get back to the gym and back to your fitness regime much quicker.
#2 - Reduced Joint Pain
The reduction of inflammation is also beneficial in regards to the joints, which can become painful after long periods of working out.
#3 - Aid Weight Loss Goals
The intake of healthy fats (such as omega-3) increases the feeling of fullness which means you’ll be less likely to snack or overeat, so supplementing with cod liver oil can potentially contribute to healthy weight loss.
#4 - Help Muscle Repair
Cod liver oil has also been shown to help increase blood flow. Increased blood flow during exercise (and post-workout) is important as this means more nutrients will be transported to the muscles, which ultimately will help increase muscle repair and muscle mass.
For increased muscle gain and better muscle repair read our article on the benefits of l-glutamine, an amino acid that provides a whole range of health boosts.
Before reading this article, you were probably wondering; what is cod liver oil good for?
Well, not only can it improve your heart health and cholesterol, but it can help with anxiety and depression, boost the condition of your skin and your eyes, and even enhance your joint health. We think that all of these cod liver oil benefits are definitely worth the slightly off-putting taste!
Be sure to read through the instructions and recommended dosage guidelines of every cod liver oil supplement that you intend to take.
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- Raeder, M.B., Steen, V.M., Vollset, S.E. and Bjelland, I. (2007). Associations between Cod Liver Oil Use and Symptoms of depression: the Hordaland Health Study. Journal of Affective Disorders, 101(1–3), pp.245–249.
- Chong, E.W.-T., Kreis, A.J., Wong, T.Y., Simpson, J.A. and Guymer, R.H. (2008). Dietary ω-3 Fatty Acid and Fish Intake in the Primary Prevention of Age-Related Macular Degeneration. Archives of Ophthalmology, 126(6), p.826.
- Galarraga, B., Ho, M., Youssef, H.M., Hill, A., McMahon, H., Hall, C., Ogston, S., Nuki, G. and Belch, J.J.F. (2008). Cod Liver Oil (n-3 Fatty acids) as an non-steroidal anti-inflammatory Drug Sparing Agent in Rheumatoid Arthritis. Rheumatology, 47(5), pp.665–669.
- Gilbert, C. (2013). What Is Vitamin A and Why Do We Need it? Community Eye Health, 26(84), p.65.
- Herr, C., Greulich, T., Koczulla, R.A., Meyer, S., Zakharkina, T., Branscheidt, M., Eschmann, R. and Bals, R. (2011). The Role of Vitamin D in Pulmonary disease: COPD, asthma, infection, and Cancer. Respiratory Research, 12(1).
- Holick, M.F. (1996). Vitamin D and Bone Health. American Institute of Nutrition., pp.1159S-1164S.
- Horrobin, D.F. (2000). Essential Fatty Acid Metabolism and Its Modification in Atopic Eczema. The American Journal of Clinical Nutrition, 71(1), pp.367s–372s.
- Huang, W.-B., Fan, Q. and Zhang, X.-L. (2011). Cod Liver oil: a Potential Protective Supplement for Human Glaucoma. International Journal of Ophthalmology, 4(6), pp.648–651.
- Kiecolt-Glaser, J.K., Belury, M.A., Andridge, R., Malarkey, W.B. and Glaser, R. (2011). Omega-3 Supplementation Lowers Inflammation and Anxiety in Medical students: a Randomized Controlled Trial. Brain, Behavior, and Immunity, 25(8), pp.1725–1734.
- Kim, Y.-I. (1996). Can Fish Oil Maintain Crohn’s Disease in Remission? Nutrition Reviews, 54(8), pp.248–252.