Supplement Detective

By Curtis Alexander, Pharm.D.

Summary: Cod liver oil benefits are numerous.  Best of all, there is ample evidence supporting cod liver oil’s use – especially in northern areas where direct exposure to sunlight during the winter months may be limited and lead to vitamin D deficiencies.

Q: What are the cod liver oil benefits – as you see them?  I always see it touted online but it seems like a sales pitch for their particular product.  I’d like a little perspective.

A: OK, I admit it.  There are a lot of supplements out there that have a lot of hype and baseless claims.  As a matter of fact, that’s part of my job here at this website is to steer people in the right direction and give them the straight scoop and raise a bright red flag when I see a scam or an over-hyped supplement.

But, in my humble opinion, cod liver oil is the real deal.  Not only is it relatively low cost but it offers a lot of benefits.

Cod liver oil, unless you are eating superbly and have more than adequate exposure to natural sunlight, is something almost everyone should supplement with in different quantities at different times of year.  And honestly, I eat healthy.  Better than most.  But even I supplement with cod liver oil.

I won’t get into a long discussion of what exactly is in cod liver oil because this question focuses more on the benefits.  But suffice it say, that cod liver oil is one of the riches sources of vitamin A, vitamin D and omega 3 fatty acids.  It’s natural.  Its inexpensive and the benefits are great.

And, speaking of benefits I’m going to try to keep this answer relatively short.  I don’t want it to read like a PhD dissertation.  It will cover the main, proven benefits of cod liver oil.  If you want to go into more detail Google offers you plenty.

Cod Liver Oil Benefits

(1)  Rickets (Vitamin D deficiency)

While almost never seen in industrialized countries nowadays – rickets was pretty common 150 years ago.  It was particularly a problem in northern hemisphere’s where exposure to sunlight was limited and the food source was primarily grain-based.

This is exactly what you had in 19th century England.  Little sun and a very grain-based diet.  Actually, one of the early researchers into rickets, Dr. E. Mellanby was researching rickets in dogs (don’t laugh – physiologically we are pretty close to dogs – particularly our digestive tracts) and discovered in addition to cereal grains promoting rickets it also had the added effect of blocking mineral absorption due to the high phytic acid content in grains and legumes.

This is why phytic acid is considered by many to be an ‘anti nutrient’ and is why I personally try to avoid grains in my own eating style.

(2)  Arthritis

Arthritis researchers in Great Britain have shown that the elongated omega 3 fatty acids in cod liver oil can reduce the pain and inflammation from arthritis.

(3)  Babies Growth and Development

Remember Dr. E. Mellanby above?  Well his wife actually did research in babies and discovered that tooth enamel will not form properly unless the baby is exposed to adequate vitamin D.  This is especially true the more cereal-based foods a baby is fed (i.e., the more cereal you give a baby the more vitamin D they will require).

(4)  Secondary Dentintion

As you and I go through life our body is able to ‘patch’ our teeth.  We know that the more vitamin D a person has the better able they are to ‘patch’ the spots on their teeth as you have up to three times more calcium in your saliva to go to work on your damaged teeth.

(5)  Pregnancy

Women who supplemented with cod liver oil during pregnancy had infants who were at lower risk for Type 1 diabetes.  Incidentally, this same effect has not been seen with women who supplemented with simple multi-vitamins.

Additionally, brain development in the newborn is dependent upon the fatty acid profile of the mothers breast milk.  This is probably one of the reasons why babies born to strict vegetarian mothers may be at risk for stunted brain development.

Also, cod liver oil is high in vitamin A which has a clear role in preventing infections.

SIDENOTE: talk to anyone who is 80 years or older and they’ll likely remember their parents giving them cod liver oil.  Despite our advances the old time doctors knew more about nutrition than we do today.

Incidentally, the practice of giving kids cod liver oil was shunned by none other than Dr. Spock who instead relied heavily on vaccines.

It’s important to note that while cod liver oil has high amounts of vitamin D it doesn’t appear to increase the vitamin D content in breast milk.

Risks During Pregnancy

Over the years women have been advised to avoid any vitamin A containing supplements for risk of the fetus developing deformities.  First of all, the deformities were associated with synthetic vitamin A – or retinoic acid.

Almost all the studies that have been done looking at vitamin A and birth defects have shown that you have to get pretty high amounts of vitamin A – in one famous study over 5,000 IU’s a day with synthetic vitamin A.  Other researchers have concluded that you would likely have to go over 10,000 IU’s per day based on the data.  Other researchers have concluded that you can safely go up to 30,000 IU’s of vitamin A a day.

In short, most dosing regimens of cod liver oil would likely give a pregnant woman somewhere in the neighborhood of 1,000 IU’s to 2000 IU’s per day.  Well within the limits of safety established by researchers.

But, the decision to take cod liver oil while pregnant and how much you should take is up to you and your doctor.  I simply mention it here because I think that there is not a strong link between natural vitamin A and teratogenicity.

(6)  Heart Disease

From what we know, it appears cod liver is not only helpful to prevent a heart attack, it can be beneficial after a heart attack.

That’s because cod liver oil alters the linings of the arteries.  In fact, every ingredient in cod liver oil from omega-3 fatty acids to vitamin A, D and K all are involved in mineral absorption, improving muscle function and elasticity in blood vessels.

Another important component involved in heart disease is inflammation.  Well, there are inflammation reducing components that are made from the EPA in cod liver oil to control the inflammation in arteries.

Work in rats has clearly shown that atheromas (artery blockers) have become smaller and the actual diameter of arteries has increased after treatment with cod liver oil.

Of course, I always caution this isn’t human studies.  But it is promising.  And, for all purposes the evidence that we have to this point for cod liver oil in heart disease is very promising.

As you can see cod liver oils has more than ample amounts of omega-3 fatty acids and important vitamins like A and D which most Americans don’t get near enough of.  Also, this isn’t an exhaustive article by any means.  There’s much more to be said about cod liver oil and the benefits it offers.  But it provides a good overview of a supplement that is inexpensive, readily available, very beneficial and with few side effects.  That’s a good combination any day.