Food Freedom Friday Edition 332 - Omega-3

The human body can make most of the types of fats it needs from other fats or raw materials. That isn’t the case for omega-3 fats. These are called essential fats—the body can’t make them and must get them from food. Foods high in Omega-3 include fish, vegetable oils, nuts (especially walnuts), flax seeds, flaxseed oil, and leafy vegetables.

Omega-3’s are an integral part of cell membranes throughout the body and affect the function of the cell receptors in these membranes. They provide the starting point for making hormones that regulate blood clotting, contraction and relaxation of artery walls, and inflammation. They also bind to receptors in cells that regulate genetic function. Likely due to these effects, omega-3 fats have been shown to help prevent heart disease and stroke, may help control lupus, eczema, and rheumatoid arthritis, and may play protective roles in cancer and other conditions.

Omega-3 deficiency is associated with lower intelligence, depression, heart disease, arthritis, cancer, and many other health problems

Omega-3 fats are a key family of polyunsaturated fats. There are three main omega-3s:

·       Alpha-linolenic acid (ALA), the most common omega-3 fatty acid in most Western diets, is found in vegetable oils and nuts (especially walnuts), flax seeds and flaxseed oil, leafy vegetables, and some animal fat, especially in grass-fed animals. The human body generally uses ALA for energy, and conversion into EPA and DHA is very limited.

·       Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that are found mainly in fish and other animal products. They are sometimes referred to as marine omega-3s.

ALA (alpha-linolenic acid)

Alpha-linolenic acid (ALA) is the most common omega-3 fatty acid in a Western diet. It’s mostly found in plant foods and is an essential precursor of EPA and DHA. ALA is found in many plant foods, including kale, spinach, purslane, soybeans, walnuts, and many seeds, such as chia, flax, and hemp. It also occurs in some animal fats. Some seed oils, such as flaxseed and rapeseed (canola) oil, are also high in ALA.

Unfortunately, this conversion process is inefficient in humans. Less than 5% of ALA gets converted to EPA, and less than 0.5% (one-half of one percent) of ALA is converted to DHA.

A common misconception, especially amongst vegetarians and vegans, is that the need for EPA and DHA can be met by consuming flax oil and other plant sources of ALA. But the conversion numbers clearly indicate that this is simply not possible.

Studies have shown that ALA supplements (like flax oil) are unable to raise plasma DHA levels in vegans, despite low DHA levels at baseline. It is likely that most vegetarians and vegans are deficient unless they are supplementing with an algae-derived source of DHA.

This is significant because researchers now believe that the majority of the health benefits we get from dietary omega-3 fats come from the longer chain derivatives

When ALA is not converted to EPA or DHA, it is simply stored or used as energy like other fats. A diet rich in ALA has been observationally linked to a reduced risk of death from heart disease, while others show an increased risk of prostate cancer. This increases risk was not associated with the other main omega-3 types, EPA and DHA, which seem to protect against this cancer.

DHA (docosahexaenoic acid)

Docosahexaenoic acid (DHA) is an important structural component of your skin and the retinas in your eyes. DHA is vital for brain development and function in childhood, as well as brain function in adults. Early-life DHA deficiency is associated with problems later on, such as learning disabilities, ADHD, and aggressive hostility

A decrease in DHA in later life is also associated with impaired brain function and the onset of Alzheimer’s disease.

DHA may have positive effects on certain conditions, such as arthritis, high blood pressure, type 2 diabetes, and some cancers. Furthermore, DHA can boost heart health by reducing blood triglycerides.

DHA is found in high amounts in seafood, including fatty fish and algae. Grass-fed animal products also contain some DHA.

Some researchers have proposed that DHA is essential, meaning it must be derived from dietary sources.

According to modern nutrition education, there are only two essential fatty acids, omega-6 linoleic acid (LA) and omega-3 alpha-linolenic acid (ALA). It is believed that as long as these two fats are present in the diet, the remainder of the longer-chain omega-3 and omega-6 derivatives can be synthesized in the body.

Theoretically possible, but, in reality the conversion is particularly inefficient. This is true even for healthy people, but is especially true for those with nutrient deficiencies, because the conversion of ALA to DHA depends on zinc, iron and pyridoxine.

The bioavailability of iron in plant sources is poor compared to animal sources, so iron deficiency is common in vegans and vegetarians. This further compounds the poor conversion of ALA to DHA.

It is possible that the primarily carnivorous diet of ancient humans, which ensured a consistently high dietary intake of DHA and AA, precluded the need to evolve efficient conversion mechanisms.

In other words, since we were eating a lot of meat and fish with pre-formed DHA, the need for an efficient conversion process was downregulated. It is far easier for the body to assimilate pre-formed DHA than it is to synthesize them from precursors.

EPA (eicosapentaenoic acid)

EPA is another long-chain omega-3 fatty acid that is conventionally believed to be responsible for the benefits of fish consumption.

Your body uses eicosapentaenoic acid (EPA) to produce signaling molecules called eicosanoids, which are involved with many physiological processes as well as reducing inflammation.

Studies indicate that fish oil, which is high in EPA and DHA, may reduce symptoms of depression. Some evidence suggests that EPA is superior to DHA in this regard

Both EPA and DHA are mostly found in seafood, including fatty fish and algae. For this reason, they are often called marine omega-3s. EPA concentrations are highest in herring, salmon, eel, shrimp, and sturgeon. Grass-fed animal products, such as dairy and meats, also contain some EPA.

Further Types Of Omega-3’s

ALA, EPA, and DHA are the most abundant omega-3 fatty acids in your diet but least eight other omega-3 fatty acids have been discovered:

·       Hexadecatrienoic Acid (HTA)

·       Stearidonic Acid (SDA)

·       Eicosatrienoic Acid (ETE)

·       Eicosatetraenoic Acid (ETA)

·       Heneicosapentaenoic Acid (HPA)

·       Docosapentaenoic Acid (DPA)

·       Tetracosapentaenoic Acid

·       Tetracosahexaenoic Acid

These fatty acids occur in some foods but are not considered essential meaning the body can synthesize them to obtain their biological effects.

Omega-3 Conversions

As previously mentioned, ALA, the most common omega-3 fat, is an essential fatty acid that is converted into EPA and DHA However, this conversion process is inefficient in humans. On average, only 1–10% of ALA is converted into EPA and 0.5–5% into DHA. Furthermore, the conversion rate depends on adequate levels of other nutrients including copper, calcium, magnesium, zinc, iron, and vitamins B6 and B7. The modern diet, especially vegetarianism, lacks many of these. In addition, some omega-6 fatty acids compete for the same enzymes needed for this process. Therefore, the high amount of omega-6 in the modern diet may reduce the conversion of ALA to EPA and DHA.

In Summary

It is logical, to draw a few conclusions:

·       DHA is the most important of the omega-3 fatty acids, and is primarily responsible for the benefits you will get from consuming them.

·       DHA is likely to be essential, which means that you must consume it in the diet to prevent disease and ensure optimal function.

·       The conversion of plant sources of ALA, such as flax seed oil, to DHA is poor in healthy people and even worse in people deficient in certain nutrients. Vegans and vegetarians are especially prone to be poor converters of ALA to DHA.

·       If you’ve been buying flax oil in the hopes that it will help, you’d be far better off putting that money towards some fish or fish oil capsules.

Dietary changes over the past century have lowered the DHA status to a state of subclinical deficiency in many people. Countless studies show that this deficiency is at least in part to blame for the rising incidence of cardiovascular disease, inflammatory disease, mental and psychiatric disorders and suboptimal neurodevelopment. This further underlies the importance of getting nutrients from animal sources where they are easily bioavailable and absorbable.