The short answer to both of our questions is "yes", with very important caveats.
The omega-3s in fish oil do not work like statins, which selectively lower only one kind of "bad" cholesterol, called LDL.
And the characterization "bad" cholesterol is a gross oversimplification of the ways in which cholesterol impacts cardiovascular risks.
It's believed that the omega-3s in fish fat reduce the risk of strokes, sudden cardiac death, and second heart attacks by doing four things:
We should note that fish oil can raise levels of LDL cholesterol slightly in people with high blood levels of triglycerides.
However, that otherwise slightly negative impact is insignificant when seen in the context of all of the effects that omega-3s exert on blood fats, blood cholesterol, arterial inflammation, blood stickiness (platelet aggregation), and other relevant risk factors for cardiovascular disease... such as the ability of omega-3s to lower levels of lipoprotein lipase, which traps LDL cholesterol in artery walls.
The skinny on cholesterol and cardio risk
Remember that when doctors talk about types of cholesterol such as LDL and HDL, they are really talking about different lipoprotein "packages” in which cholesterol is carried.
The body uses high-density lipoproteins (HDLs) to remove cholesterol from the blood, and it uses various kinds of low-density lipoproteins (LDLs) to carry cholesterol through the blood.
Having high levels of HDL cholesterol is good for cardiovascular health, but it is critical to understand that having "high” levels of LDL cholesterol is not inherently unhealthful.
In fact, the statistical links between LDL levels and heart risk are weak, with many persons dying from heart disease despite having "low” cholesterol levels, and vice versa.
Instead, the arterial plaque-buildup that defines arteriosclerosis and resulting cardiovascular disease gets created when LDL and other low-density carriers of cholesterol become oxidized by free radicals.
And those free radicals result from inflammation in the artery wall and blood.
This is why researchers at the National Institutes of Health (and around the world) increasingly point to excessive—hence, pro-inflammatory, artery-irritating—intake of omega-6 fatty acids as the true nutritional cause of cardiovascular disease.
(Omega-6 fatty acids abound in common vegetable oils, the packaged and prepared foods made with these oils, and in grain-fed meats, poultry, and farmed fish.)
Of course, other factors—primarily stress, sedentary lifestyles, diets high in empty calories, and genetic profiles—also play major roles in cardiac risk.
How omega-3s affect cholesterol
Omega-3s do not "lower cholesterol” in the way that statin drugs (e.g., Lipitor)—which lower LDL cholesterol levels very substantially—are designed to do.
In fact, omega-3s often raise levels of LDL cholesterol slightly in people with high triglyceride levels. But, for the reasons we just explained, this is not in itself a cause of concern.
Omega-3s tend to lower levels of all non-HDL types of cholesterol.
This effect of omega-3s is very significant, for three reasons (Bays H 2008; Bays HE et al. 2008):
Cholesterol and cardiovascular health: exploding common myths
Back in 1984, the National Institutes of Health issued a "consensus statement” on heart disease, in which the agency advised the American public that the best way to prevent heart disease was to reduce their consumption of cholesterol levels and saturated fats.
In fact, while there was no such scientific consensus, there were mountains of evidence to the contrary.
Most folks are surprised to learn that many people with "unhealthy” cholesterol levels never suffer from heart attacks or die from cardiovascular disease, while the reverse is also true: that is, many people with low cholesterol levels have cardiovascular disease and/or die from sudden cardiac death.
While people are somewhat more likely to have a heart attack when they have one of three "cholesterol profiles”—1) very high total cholesterol levels, 2) high levels of small, dense LDL cholesterol (which can imbed in artery walls more easily), and 3) high levels of oxidized LDL—the connection between total cholesterol levels or cholesterol profiles and adverse cardiovascular events or cardiac deaths is much weaker than we're led to believe.
Triglyceride levels, blood stickiness (platelet activation), and vulnerability to arrhythmias are equally powerful predictors of the risks of heart attacks, sudden cardiac death, and strokes… and fish oil is proven to reduce all of these risk factors substantially.
In addition, insulin and leptin resistance and high triglyceride levels appear to rival cholesterol levels as predictors of cardiovascular risk, while inflammation, impaired immune-cell response to arterial plaques, and homocysteine levels are also key factors.
Most of the cholesterol in the blood comes not from foods, but from the liver, where it is created in response to signals from the body: signals influenced by dietary fats and many other factors.
Dietary cholesterol and saturated fats are not inherently artery-clogging substances, but both become problematic in the context of the average American diet, which is imbalanced deeply in key respects:
The vast preponderance of evidence indicates that the heart disease epidemic afflicting Americans has little to do with their intake or blood levels of cholesterol.
Instead, the evidence points to the American diet's dearth of anti-inflammatory, anti-arrhythmic omega-3s and wildly excessive intake of pro-inflammatory omega-6 fatty acids—from cheap vegetable oils (corn, soy, safflower, cottonseed, canola) used in home and restaurant cooking and in packaged foods—trans fats (from hydrogenated oils), sugars, and refined corn and wheat starches.
The reason why high blood levels of "good” HDL cholesterol are the newest measure of heart-health is that HDL cholesterol spirits excess LDL cholesterol out of sticky blood, thereby keeping it from being oxidized and/or sticking to arterial lesions.
And arterial lesions are also caused in large part by the chronic lack of dietary omega-3s and excess of dietary omega-6 and trans fats: an imbalance that promotes wear-and-tear damage to arteries, plaque build-up, and clot formation.
Statins and cardiac risks
If high total and LDL cholesterol aren't the real problem, why are statins—invariably described as "cholesterol-lowering” agents—the leading heart drugs of today?
Despite the conveniently simple "cholesterol-lowering” label applied to statins, researchers agree that most of these agents' cardiac risk-reduction effects do not flow from their power to lower cholesterol by blocking internal creation of cholesterol.
Instead, the benefits of statins drugs derive from their anti-inflammatory and anti-clotting effects, and from their beneficial impacts on endothelial (artery lining) function (Patel TN et al 2007, Stoll G and Bendszus M 2006).
As we've described in previous articles, omega-3s appear to have comparable life-preserving power. (see "Does Statins' Super-Star Status Make Sense?” and "Omega-3s Seen Rivaling Statins at Reducing Risk of Death”.)
Two years ago, German researchers published their review of 97 clinical trials, and came to this conclusion: "Statins and n-3 fatty acids [omega-3s] are the most favorable lipid-lowering interventions with reduced risks of overall and cardiac mortality.” (Studer M et al 2005)
As we reported, the review showed that statins hold a clear edge with regard to preventing first heart attacks, which omega-3s are not proven to prevent significantly.
However, the review found that omega-3s reduce heart-related deaths about as effectively as statins:
The reviewers also found that omega-3s decrease the risk of death from all causes, almost as much as statins.
Although adverse liver and muscle effects from statins are relatively rare, these drugs reduce the liver's production of coenzyme Q10: a key nutrient for muscle-heart health and mitochondrial (energy-producing) functions in all cells.
While tests do not show that statin therapy reduces blood or tissue levels of CoQ10 or mitochondrial function consistently, researchers haven't conducted tests that reflect high, real-world statin doses or look in the tissues most affected by statins (Hargreaves IP et al 2005).
We do NOT suggest that you should ignore a doctor's advice to take statins. We DO suggest that you read up on statins and the weakness and complexity of the links between cholesterol levels and cardiac risks before you take the advice blindly.