Omega-3 Fatty Acids and Osteoporosis

Reviewed By:
Dr. Liz Lipski – AlgaeCal Scientific Advisory Board Member
PhD, CNS, FACN, IFMP, BCHN, LDN
Professor and Director of Academic Development, Nutrition programs in Clinical Nutrition at Maryland University of Integrative Health.

About the Advisory Board Member

You know they’re good for you, and you’ve probably heard that fish like salmon are rich in them, but what exactly are omega-3s, and why should you care?

Omega-3 fatty acids are one of the cornerstone nutrients you need for optimal bone health – and, quite frankly, for optimal health in general. These unique fats can benefit all kinds of inflammatory conditions and support overall immunity [1].  

Omega-3 Fatty Acids

Omega-3 fatty acids fall under a category of fats known as “essential fatty acids.” Why are they essential? These types of fats are found in nature and are vital for the proper functioning of your body, but you cannot produce them on your own. Therefore, it is essential that you get them through your diet [2]. Seafoods, especially oily fish, are the richest food sources of omega-3s. 

Omega-3 fatty acids include:

• ALA (α-Linolenic acid)
• EPA (eicosapentaenoic acid)
• DHA (docosahexaenoic acid)

ALA is the “parent” compound of the omega-3 fatty acids. From ALA, the body can synthesize longer chain omega-3s, EPA and DHA. However, this synthesis is not particularly efficient – more on that later! First, let’s look at what these omega-3s can do for your bones.

How Do Omega-3 Fatty Acids Protect Your Bones?

One of the most significant claims to fame for DHA and EPA is their inflammation-fighting activity. While ALA is beneficial in its own right, EPA and DHA are true superstars when it comes to inflammation and bone health. 

When inflammatory chemicals are high, it increases the activity of osteoclast cells (the cells that break down bone), which is why inflammation is so detrimental to bone health [3]. 

By reducing inflammation, EPA and DHA help tame osteoclast activity and preserve bone integrity. 

At the same time, studies show that EPA and DHA can increase the activity of osteoblasts – the cells responsible for building new bone [4].

In a 2016 study, 117 healthy, postmenopausal women were divided into two groups; one receiving a DHA and EPA-enriched milk and one receiving milk that was only fortified with vitamins A and D. 

After 12 months on their respective milk supplements, the intervention group receiving the omega-3 fats saw a 28.20% decrease in C-reactive protein (a marker for inflammation) and a 17.64% decrease in an inflammatory protein named RANKL which is responsible for activating osteoclasts (bone destroying cells) [5].

In another study, investigators aimed to determine the impact that omega-3 fatty acids had on bone mineral density (BMD). First, they had their volunteers (a group of 1,865 Spanish women aged 20 to 79) undergo a dual-energy X-ray absorptiometry (DEXA) to measure their bone mineral density (BMD). 

Next, they had each woman record her dietary intake of calcium, vitamin D, the omega-3s (ALA, EPA, and DHA), and the omega-6s (LA and arachidonic acid) in a food journal.

By comparing the results of the DEXA and food journals, the study showed that the women with normal bone density consumed more DHA and EPA than those with osteoporosis or osteopenia. Furthermore, the women with osteopenia consumed more EPA and DHA combined than those with osteoporosis.

Although, due to the study design, no firm conclusions could be drawn about the impact of omega-3 fats on osteoporosis, the researchers did conclude that omega-3 fatty acid intake was “significantly associated” with BMD at both the hip and the lumbar spine in women with a normal bone density and women with osteopenia [6]. 

The Omega-3 to Omega-6 Ratio

While omega-3 fatty acids are well-known for their anti-inflammatory activity, another class of omega fats is the omega-6 fatty acids, which have a less popular reputation. 

Omega-6 fats aren’t inherently bad, but they can cause inflammation, particularly when you have more omega-6 fats than omega-3 in your diet. And this is becoming more prevalent as our diets have become ridden with processed foods, which are also associated with increased risk of heart disease, stroke, cancer, and overall mortality. Vegetable oils, salad dressings, frozen meals, baked goods, salty snacks, protein bars, and fried foods are among the top culprits for overloading on omega-6.  

Omega-6 fatty acids include:

• LA (linoleic acid)
• AA (arachidonic acid)
• GLA (gamma-linolenic acid)

LA is the “parent” compound of the omega-6 fatty acids. From LA, the body can synthesize longer chain omega-6s, AA and GLA.

While LA and ALA tend to promote inflammation, GLA is actually shown to have anti-inflammatory activity [7]. However, the American diet tends to be much higher in the inflammatory forms, with about 90% of omega-6 intake coming from LA [8].  

How Can Omega-6 Fatty Acids Harm Your Bones?

One of the primary ways in which omega-6 fats can harm your bones is due to their impact on a line of stem cells found in your bone marrow called mesenchymal stem cells (MSCs).

MSCs can become osteoblasts (bone-building cells) or adipocytes (fat cells). Clearly, you’d prefer healthy bones to unhealthy amounts of fat.

But what makes your MSCs become osteoblasts or adipocytes? That’s where the omega 3s and omega 6s come in.

MSCs are influenced by the compounds derived from both omega-6 (linoleic acid [LA]) and omega-3 (alpha-linolenic acid [ALA]) fatty acids. While signals from omega-6 fat steer MSCs in the direction of adipocytes, signals from omega-3s steer them in the direction of osteoblasts.

This means that the more omega-6 are around, the fewer bone-building cells you get, and the more fat cells are produced – not ideal conditions for bone health [9].

Arachidonic acid (AA) can be particularly troublesome as this omega-6 fat not only inhibits the formation of osteoblasts but also lowers the production of an anti-inflammatory compound called osteoprotegerin (OPG) produced by mature bone-building osteoblasts.

When OPG is active, it inhibits osteoclast formation, giving your bone-building cells a chance to do their job. When it is inactive, however, osteoclasts are allowed to proliferate, and bone breakdown can easily outpace bone building. 

The Omega-6 to Omega-3 Ratio

Although they are inflammatory, omega-6s still play vital roles in our body, such as supporting a healthy immune system. So, the goal is not to avoid them entirely. Instead, we want to aim for a balanced intake of omega-6s and omega-3s. But while our intake of omega-3 fats has significantly declined in the last 150 years, our consumption of omega-6 fatty acids has consistently climbed.   

Ideally, we would be consuming a ratio of around 1:1 omega-6 to omega-3, and no more than 4:1. Nutritious foods provide omega-6s and omega-3s in this healthy ratio. It’s the highly processed foods that skew this ratio, bringing today’s consumption closer to 15:1 – a far cry from where we need to be for optimal health!

Are You Getting Enough Omega-3s?

There’s currently no universal recommendation for the daily intake of EPA and DHA. Recommended intakes from expert organizations vary from 0.3-4 g/day, with some being geared towards specific health outcomes. For example, the European Food Safety Authority suggests 3 g/day to lower blood pressure and 2-4 g/day to lower triglyceride levels [10].

The top food sources of EPA and DHA are predominantly seafoods, especially oily fish. Refer to the table below to see which seafood contains the most:

Top Food Sources of EPA and DHA

The most abundant dietary sources of EPA and DHA are wild-caught cold-water fatty fish. While wild fish consume smaller fish and algae (which are naturally rich in omega-3s), farmed fish consume fish feed– which is generally rich in omega-6 fats. 

In fact, one study found that farmed salmon contained three times more fat than wild salmon, with substantially lower omega-3 fats (8.9% vs. 21.1%). The same study also showed that the omega-6 to omega-3 ratio was much higher in the farmed salmon than in the wild [11]. 

Ultimately, with wild-caught fish (which includes most canned salmon, unless labeled as Atlantic salmon), you get more omega-3s, less omega-6, and more protein per pound – that’s a good deal. 

That said, even wild-caught fish have a drawback – mercury. 

Mercury accumulates in fish in a form that’s water-soluble and highly bioavailable (meaning easily absorbed by us). When our bodies accumulate mercury, it tends to deposit in our kidneys, causing all types of issues, including potential bone loss due to the role that the kidneys play in vitamin D and calcium homeostasis [12]. 

So, as you can see from the table, it can be challenging to obtain optimal amounts of EPA + DHA on a daily basis. Even if you’re a fish-lover! Not to mention the concerns around mercury that would come with consuming that amount of fish daily. 

This is where high-quality omega-3 supplements come in to make up the difference. 

But What About Vegan Food Sources of Omega-3?

While DHA and EPA are found primarily in animal foods, ALA is the main omega-3 found in plant-based foods, particularly nuts and seeds, making it much easier to obtain from dietary sources. 

Unfortunately, although ALA may be converted into DHA and EPA, studies show that the conversion rate is very low – approximately 6% for EPA and 3.8% for DHA. This means that you can consume all the flaxseeds you like, but you’ll never get close to the amount of DHA your body requires to function optimally. 

Furthermore, studies show that when omega-6 is in the mix at a higher ratio than omega-3, it can further complicate the conversion of ALA to DHA and EPA. Since most plant-based sources of omega-3s will come with a fair portion of omega-6, this makes getting EPA and DHA from vegan foods all the more challenging [13].

Test Your Omega-3 Levels

Most people in the west are consuming inadequate levels of omega-3s. In fact, research shows that the average intake of omega-3 fats has decreased to less than 20% of what it was 150 years ago. Furthermore, about 95-99% of the population gets fewer omega-3s than are required for optimal health [14].

Why?

Because the western diet is generally devoid of omega-3 fats. As mentioned, even our fish supply is now tampered by farmed fishing that produces higher levels of omega-6 than omega-3 fatty acids. 

If you’re interested in figuring out exactly what your omega-3 levels are, there’s a simple at-home test called the OmegaQuant Test. OmegaQuant is a test that’s used by the NIH for their own clinical studies and provides accurate results without having to go to a lab.

Once you know your omega-3 levels, you’ll have a more accurate picture of the right course of action to keep your omega-3s in a healthy range. For most people, this means adding an omega-3 supplement. 

To learn how to choose the best omega-3 supplement, read this article.

Takeaway

Omega-3 and Omega-6 fatty acids play various roles in our bodies, primarily influencing inflammation and the associated immune responses. This can directly impact the health of your bones and every other system in your body. 

Working in direct opposition, omega-3 and omega-6 fats can either promote healthy, strong bones (omega-3) or promote the production of fat cells in your bone marrow (omega-6). While both of these types of fats are necessary for optimal health, if your diet is high in omega-6 and low in omega-3, you could get into big trouble. Unfortunately, due to our modern food supply, it looks like everyone is consuming an omega-6-rich diet these days. 

The good news is that there’s plenty you can do to get your omega-3 ratio up. In addition to adding high-quality seafood to your diet and limiting the amount of processed and refined foods in your diet, omega-3 supplements offer a simple solution that your bones (and the rest of your body) will thank you for.

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FAQs

References

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5. Fonolla-Joya, J., Reyes-García, R., García-Martín, A., López-Huertas, E., & Muñoz-Torres, M. (2016). Daily intake of milk enriched with n-3 fatty acids, oleic acid, and calcium improves metabolic and bone biomarkers in postmenopausal women. Journal of the American College of Nutrition, 35(6), 529-536.
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8. https://lpi.oregonstate.edu/mic/other-nutrients/essential-fatty-acids
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13. Gerster, H. (1998). Can adults adequately convert a-linolenic acid (18: 3n-3) to eicosapentaenoic acid (20: 5n-3) and docosahexaenoic acid (22: 6n-3)?. International journal for vitamin and nutrition research, 68(3), 159-173.
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