In the second article in this series, I explained why omega-3 essential fatty acids, EPA and DHA, are truly essential for healthy bones. We discussed why, as we age, not getting enough omega-3s causes sarcopenia. Sarcopenia is a condition in which we produce fat instead of muscle and bone. You won’t be surprised to know that sarcopenia greatly contributes to unhealthy aging and bone loss.
We also discussed why when enough EPA is available to compete with the omega-6 fatty acid, arachidonic acid (AA), for the COX-2 and LOX-5 enzymes, less pro-inflammatory and more anti-inflammatory and inflammation-ending compounds are produced.
When enough EPA/DHA is consumed daily to result in a ratio of omega-6: omega-3 of no greater than 4:1, your metabolism will shift to one that favors:
- an anti-inflammatory response
- prevents chronic low grade inflammation
- quickly resolves acute inflammation
- puts a damper on the production of osteoclasts (the specialized cells that break down bone)
- and encourages your mesenchymal stem cells to become bone-building osteoblasts rather than fat cells
In this article, we’ll see why the modern Western diet (also called the Standard American diet or, appropriately, the“SAD”) is not going to help you get the EPA/DHA you need.
The SAD is not only loaded with bone-busting omega-6s, but is severely lacking in bone-building omega-3s. This is a key reason why the SAD promotes our accumulation of fat and loss of bone as we age.
Processed foods punish our bones with pro-inflammatory omega-6s.
The parent omega-6, linolenic acid (LA), is abundant in all the vegetable oils used in processed foods. Foods such as
- taco shells
- breads rolls
- pie crusts
- frozen dinners
- soups, etc.
Omega-6 (LA)-rich vegetable oils are also abundant in salad dressings and sauces.
Many animal products contain high doses of omega-6’s pro-inflammatory child, arachidonic acid.
In addition, pre-formed pro-inflammatory arachidonic acid (AA) is present in meats. For example beef, lamb, pork, chicken, duck, turkey, and also in eggs and fish, particularly farmed fish.
Also, it should be mentioned that the amount of pre-formed pro-inflammatory AA present in meats, eggs and farmed fish is greatly impacted by the diet given the animal from which the meat, eggs or farmed fish were derived.
The AA content of beef from a pastured cow will be significantly lower than the AA content of beef from a corn-fed, feed lot cow. Similarly, the AA content of meat and eggs from free-range chickens will be much less than that from chickens fed cornmeal. In one recent study, AA content ranged from 20 milligrams in a 3-ounce serving of rainbow trout fed a diet rich in flaxseed oil (high in ALA, the parent omega-3) to 138 milligrams in a 3-ounce serving of chicken fed a corn-based diet (high in omega-6s), to 681 milligrams in a 3-ounce serving of rainbow trout fed a commercial grain/corn (omega-6-rich) feed mixture.
Food sources of the parent omega-3, ALA, are few and less frequently eaten.
In contrast to the high levels of omega-6s in the vegetable oils used in processed foods, in the eggs and meat from animals fed corn and grains, and in farmed fish, far fewer frequently eaten foods contain either ALA, the parent omega-3, or pre-formed EPA and DHA.
ALA is found in greatest amounts and in the highest ratio to omega-6 in:
- Flaxseed and its oil
- Brussel sprouts
- Collard greens
ALA is also found in walnuts, pumpkin seeds, soybean oil, canola oil, and corn oil, but these foods contain lots more linolenic acid (LA, the parent omega-6) than ALA (the parent omega-3). And this results in little or no ALA being converted to EPA and DHA.
Why? Because COX-2 (the enzyme we discussed in the second article in this series — Omega-3s Prevent Our Bones and Muscles from Turning into Fat as We Age — that produces the offspring of both AA and EPA/DHA), prefers to work with AA. For this reason, when we consume a food that contains more omega-6 than omega-3, all the COX-2 will first be used to produce pro-inflammatory compounds from AA, leaving very little or even no COX-2 to produce anti-inflammatory compounds from the smaller amounts of ALA in the food.
Humans, at best, produce only tiny amounts of EPA/DHA from ALA
Furthermore, humans are able to convert just a tiny bit of the — already very small amount of — ALA in plant foods into EPA and DHA. One study reported that only 6% of dietary ALA was converted to EPA and just 3.8% was converted to DHA in humans eating a diet high in saturated fat. But, even a diet high in any of the omega-6 rich vegetable oils mentioned above (e.g., soy, corn, safflower, canola) – and this is the diet most all of us eat nowadays – greatly inhibits ALA’s conversion to EPA and DHA. Research has shown that the conversion of ALA to EPA and DHA is reduced by 40% to 50% when the diet is rich in omega-6-oils – as is the Standard American or western diet.
What does all this mean for your bones?
In our modern world, in which the food supply is overloaded with omega-6, the tiny amounts of ALA in plant foods, most of which are not regularly eaten by the majority of us, cannot provide us with enough EPA and DHA to protect our bones.
Wild caught fish, the best dietary sources of EPA/DHA
Can we get enough of the long-chain omega-3s, EPA and DHA, we need to maintain healthy muscles and bones from other dietary sources? While it’s possible, it’s not practical. To ensure optimal intake of EPA and DHA, we need to take a supplement. Here’s why.
The only good dietary sources of EPA and DHA are wild caught cold water fatty fish, such as sardines, salmon, sablefish, halibut and tuna.
It’s important to specify that the fish be “wild caught” because, as mentioned above, the amount of EPA and DHA in fish (and in the meats derived from other animals and in eggs) is highly dependent on their diet. If the fish eat algae, sea plants, and other smaller fish that are rich in omega-3s, they will produce and store more EPA and DHA in their tissue.
Farmed fish contain as much or more omega-6 than omega-3.
Farmed fish are not a good source of usable omega-3s. Why?
Because the food farmed fish are given is loaded with omega-6-rich oils, so farmed fish contain at least as much, and typically more omega-6 than omega-3.
Remember, as discussed in the second article in this series, lots of omega-6 along with little omega-3 results in COX-2 acting as inflammation-promoting Mr. Hyde. Since COX-2 prefers to work on AA rather than EPA or DHA, when you eat a piece of farmed salmon or tilapia, for example, all available COX-2 will be used to produce pro-inflammatory compounds from AA, leaving none to produce anti-inflammatory compounds from the smaller amount of EPA and DHA in the fish.
Plus, there’s another serious problem with relying on fish, even wild caught fish, for our supply of EPA and DHA: mercury.
Even wild-caught fish may contain bone-destructive mercury
Mercury accumulates in fish in a form that is water-soluble and highly bioavailable (meaning easily absorbed by us). We absorb 7% to 15% of the mercury in the fish we eat. And mercury accumulates in us just like it does in fish. In humans, mercury deposits mainly in our kidneys, where it causes serious damage and promotes bone loss.
Mercury’s accumulation in our kidneys causes bone loss because mercury-caused damage to the kidneys disrupts essential kidney functions, including the kidney’s activation of vitamin D. When we consume vitamin D or produce it from our skin’s exposure to sunlight, the vitamin D is not yet in its active form. To become active, vitamin D must be modified, and this happens in two steps, the first one in the liver, where vitamin D is partially activated, and the second one in our kidneys where vitamin D is changed into its fully active form.
To be able to increase our absorption of calcium from the intestines and its reabsorption from the kidneys, vitamin D must be in its activated form. By harming the kidneys and thus preventing vitamin D’s activation, mercury causes blood levels of calcium to drop. And since calcium is required not just for healthy bones, but also for many essential activities throughout the body (for example, enabling our muscles-including our heart muscle—to contract), when blood levels of calcium drop, this triggers its withdrawal from bone to restore calcium to the level we must have in the bloodstream.
To minimize our consumption of mercury, we need to be careful which fish we eat, and it can be difficult to safely eat enough fish to provide optimal amounts of EPA and DHA. Some types of fish contain very little or at least lower levels of mercury and can be eaten in moderate amounts without risk of harm to our kidneys and bones, while other types of fish contain high levels of mercury and are best avoided. The following list can help you choose the best fish for your bones’ health.
You’d have to eat at least 2 servings of fish every day to get the amount of EPA/DHA needed for healthy bones
Current research indicates the health benefits provided by omega-3s are associated with intakes of 2.6 – 3 grams or more of EPA and DHA per day. As you can see from the table below, you’d need to consume at least two 3-ounce portions of the fish that are low in mercury every day to safely provide enough EPA and DHA to beneficially impact the health of your bones. That’s a lot of fish!
Is there any practical way we can easily consume enough EPA and DHA to prevent bone loss and ensure that we continue to produce bone and muscle rather than fat as we age?
Yes, we need to take a supplement that will provide us with at least 2.6 grams of EPA/DHA per day, the amount research has shown provides the most benefit.
In our next article, we’ll talk about what you need to look for when choosing your EPA/DHA supplement.
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https://www.nrdc.org/stories/mercury-guide, accessed 4-12-14