Intake of fish and marine n-3 polyunsaturated fatty acids and risk of breast cancer: meta-analysis of data from 21 independent prospective cohort studies.


Abstract

Objectives To investigate the association between intake of fish and n-3 polyunsaturated fatty acids (n-3 PUFA) and the risk of breast cancer and to evaluate the potential dose-response relation.

Design Meta-analysis and systematic review of prospective cohort studies.

Data sources PubMed and Embase up to December 2012 and references of retrieved relevant articles.

Eligibility criteria for selecting studies Prospective cohort studies with relative risk and 95% confidence intervals for breast cancer according to fish intake, n-3 PUFA intake, or tissue biomarkers.

Results Twenty six publications, including 20 905 cases of breast cancer and 883 585 participants from 21 independent prospective cohort studies were eligible. Eleven articles (13 323 breast cancer events and 687 770 participants) investigated fish intake, 17 articles investigated marine n-3 PUFA (16 178 breast cancer events and 527 392 participants), and 12 articles investigated alpha linolenic acid (14 284 breast cancer events and 405 592 participants). Marine n-3 PUFA was associated with 14% reduction of risk of breast cancer (relative risk for highest v lowest category 0.86 (95% confidence interval 0.78 to 0.94), I2=54), and the relative risk remained similar whether marine n-3 PUFA was measured as dietary intake (0.85, 0.76 to 0.96, I2=67%) or as tissue biomarkers (0.86, 0.71 to 1.03, I2=8%). Subgroup analyses also indicated that the inverse association between marine n-3 PUFA and risk was more evident in studies that did not adjust for body mass index (BMI) (0.74, 0.64 to 0.86, I2=0) than in studies that did adjust for BMI (0.90, 0.80 to 1.01, I2=63.2%). Dose-response analysis indicated that risk of breast cancer was reduced by 5% per 0.1g/day (0.95, 0.90 to 1.00, I2=52%) or 0.1% energy/day (0.95, 0.90 to 1.00, I2=79%) increment of dietary marine n-3 PUFA intake. No significant association was observed for fish intake or exposure to alpha linolenic acid.

Conclusions Higher consumption of dietary marine n-3 PUFA is associated with a lower risk of breast cancer. The associations of fish and alpha linolenic acid intake with risk warrant further investigation of prospective cohort studies. These findings could have public health implications with regard to prevention of breast cancer through dietary and lifestyle interventions.

Discussion

In this meta-analysis dietary intake of marine n-3 polyunsaturated fatty acids (PUFA), but not alpha linolenic acid (ALA), was associated with a lower risk of breast cancer. Fish consumption was not associated with risk. Dose-response analyses indicated a 5% lower risk of breast cancer per 0.1g/day or 0.1% energy/day increment of dietary marine n-3 PUFA, but no significant trend for ALA or fish intake. To the best of our knowledge, this is the first time meta-analysis has systematically and quantitatively evaluated the association between intake of fish and n-3 PUFA and risk of breast cancer.

Source: BMJ

Serum long-chain n-3 polyunsaturated fatty acids, methylmercury and blood pressure in an older population.


Fish or fish oil consumption has been associated with lower blood pressure. Fish may also contain methylmercury, which has been associated with cardiovascular diseases and higher blood pressure. Our aim was to study the associations of serum long-chain n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA), mainly reflecting fish or fish oil intake, and hair mercury concentration with blood pressure. Data were available for 848 men and 909 women from the Kuopio Ischaemic Heart Disease Risk Factor Study, aged 53–73 years. We excluded participants with ischemic heart disease, stroke, diabetes or hypertension treatment, leaving 396 men and 372 women. Log-transformed values were used to study the associations. The mean serum concentrations were 1.63% (s.d. 0.91) for EPA, 0.77% (s.d. 0.16) for DPA and 2.73% (s.d. 0.90) for DHA of all serum fatty acids. Multivariate-adjusted serum EPA+DPA+DHA was associated with lower systolic blood pressure (β=−4.50, 95% confidence interval (CI) −8.02–−0.99) and pulse pressure (β=−4.41, 95% CI −6.95–−1.87), but not with diastolic blood pressure (β=−0.45, 95% CI −2.31–1.52). The associations were similar with EPA, DPA and DHA evaluated individually. The mean hair mercury concentration was 1.42 μg g−1 (s.d. 1.54). Hair mercury was not associated with blood pressure and it did not modify the association between PUFA and blood pressure. These results suggest that higher serum long-chain n-3 PUFA concentration has a modest inverse association with blood pressure in older men and women.

Source: Hypertension Research/nature.

 

 

 

 

Which Oil Will Help You Absorb Nutrients Better?


You’re probably aware that in order to absorb all of the extremely healthy fat-soluble nutrients in your food, compounds like lutein, beta-carotene and vitamin E, for instance, you’ve got to eat them with some fat.

So perhaps you always add olive oil to your salads or eat your veggies with butter to absorb all of those valuable nutrients.

This is a smart health move, but did you know that not all oils are created equal when it comes to nutrient absorption? Some work better than others and can actually enhance the amount of nutrients your body receives from the food you eat.

Coconut Oil is Superior in Enhancing Nutrient Absorption

A new animal study compared the effects of feeding coconut oil (a saturated fat) versus safflower oil (a polyunsaturated fat) on the absorption of carotenoids from tomatoes. Coconut oil enhanced tissue uptake of tomato carotenoids to a greater degree than safflower oil, a benefit the researchers suggested may be due to coconut oil’s medium chain fatty acids (MCFAs):1

“These results may have been due to the large proportion of medium chain fatty acids in coconut oil, which might have caused a shift in cholesterol flux to favor extrahepatic carotenoid tissue deposition.”

Coconut oil is nature’s richest source of healthy MCFAs. By contrast, most common vegetable or seed oils are comprised of long chain fatty acids (LCFAs). There are several reasons why these long-chain fatty acids are not as healthy for you as the MCFAs in coconut oil.

Why Choose an Oil Like Coconut Oil?

In addition to its ability to potentially allow you to absorb more antioxidants and other nutrients from your food, MCFAs are smaller than LCFAs, which means they permeate cell membranes easily, and do not require lipoproteins or special enzymes to be utilized effectively by your body. Further:

  • MCFAs are easily digested, thus putting less strain on your digestive system. This is especially important for those of you with digestive or metabolic concerns.
  • MCFAs are sent directly to your liver, where they are immediately converted into energy rather than being stored as fat.
  • MCFAs in coconut oil can actually help stimulate your body’s metabolism, leading to weight loss.

There are numerous studies showing that MCFAs promote weight loss, including one study that showed rats fed LCFAs stored body fat, while rats fed MCFAs reduced body fat and improved insulin sensitivity and glucose tolerance.2 Yet another study found that overweight men who ate a diet rich in MCFAs lost more fat tissue compared to those eating a high-LCFA diet, presumably due to increased energy expenditure and fat oxidation from the MCFA intake. Researchers concluded:3

“Thus, MCTs may be considered as agents that aid in the prevention of obesity or potentially stimulate weight loss.”

Coconut oil earns even more “points” because it’s rich in lauric acid, which converts in your body to monolaurin – a compound also found in breast milk that strengthens immunity. Caprylic acid, another coconut fatty acid present in smaller amounts, is another antimicrobial component. Plus, using coconut oil as your primary cooking oil is important because it is the only one that is stable enough to resist heat-induced damage. When choosing a coconut oil, make sure you choose an organic coconut oil that is unrefined, unbleached, made without heat processing or chemicals, and does not contain GM ingredients. On the other hand, in the case of LCFA-rich vegetable oils:

  • LCFAs are difficult for your body to break down — they must be packaged with lipoproteins or carrier proteins and require special enzymes for digestion.
  • LCFAs put more strain on your pancreas, your liver and your entire digestive system.
  • LCFAs are predominantly stored in your body as fat.
  • LCFAs, when oxidized, can both injure and deposit within arteries, contributing to both blood vessel inflammation and plaque build-up.

Polyunsaturated fats, which include common vegetable oils such as corn, soy, safflower, sunflower and canola, are absolutely the worst oils to use in cooking. These omega-6 oils are highly susceptible to heat damage because of their multiple double carbon bonds. If you’ve been shunning coconut oil because it’s a saturated fat, you needn’t worry. Saturated fats are actually essential and quite good for you.

Enzymes: Another Tool to Enhance Nutrient Absorption

Enzymes are composed of amino acids and are secreted by your body to help catalyze functions that would normally not occur at physiological temperatures. They literally make magic happen and are absolutely vital to your life.

More than 3,000 different enzymes have been identified, and some experts believe there may be another 50,000 we have yet to discover. Each enzyme has a different function—like 3,000 specialized keys cut to fit 3,000 different locks. In this analogy, the locks are biochemical reactions, which include not only energy production and absorption of oxygen, but getting nutrients into your cells.

Chronic malabsorption can lead to a variety of illnesses. Think about it—if your body doesn’t have the basic nutritional building blocks it needs, your health and ability to recover from illness will be compromised. Enzyme deficiency results in poor digestion and poor nutrient absorption. This creates a variety of gastrointestinal symptoms, including:

  • Constipation
  • Bloating
  • Cramping
  • Flatulence and belching
  • Heartburn and acid reflux

Many people are, unfortunately, lacking in the enzyme department, as diets heavy in cooked, processed, and sugary foods, combined with overuse of pharmaceutical drugs such as antibiotics, deplete your body’s ability to make enzymes. Heating your food above 116 degrees F also renders most enzymes inactive for destroys them. This is one of the reasons it’s so important to eat your foods raw. Raw foods are enzyme-rich, and consuming them decreases your body’s burden to produce its own enzymes. The more food that you can eat raw, the better.

A Healthy Gut Encourages Optimal Nutrient Absorption

Similar to enzymes, your gut flora, the microorganisms living in your intestines, continually and dynamically affect your health. In fact, these beneficial bacteria secrete essential enzymes for us. The Lactobacillus genus of probiotics, for instance, got their name from the fact that they break down lactose (milk sugar) into lactic acid with the enzyme lactase. This, in fact, is one reason why culturing was invented in the first place, as only a limited number of individuals with a particular European genotype are capable of producing the lactase enzyme late into life — most lose the ability soon after weaning from breast milk.

Good bacteria that you take in, either from fermented foods or in supplement form, also prevent the growth of less desirable ones by competing for both nutrition and attachment sites in the tissues of your alimentary canal. These friendly bacteria also aid digestion and nutrient absorption so that you’re able to get more benefit from the foods you eat.

In fact, without good gut bacteria, your body cannot absorb certain undigested starches, fiber, and sugars. The friendly bacteria in your digestive tract convert these carbohydrates into primary sources of important energy. These bacteria also produce a secondary layer of indispensable fermentation byproducts such as bacteriocins (which fight infection), beta glucans (which modulate immunity), and the entire B group vitamin series, to name but only a few of the nutrients they are capable of producing for us. Through this continual process of biotransformation that happens 24-7 in our gut, we are in many ways vitamin- and “medicine”-producing factories!

Eating fermented vegetables, and other fermented foods, like kefir, regularly is one of the best ways to nourish your gut flora for optimal nutrient absorption.

The common thread that you may have noticed here is a traditional, healthy diet. When you eat the foods your body is designed for, foods like coconut oil and other fresh, raw, minimally processed sources of fat, protein and healthy carbs, you will naturally encourage your body to utilize all that it can from the healthy foods you eat. So remember, when you need an oil to add to your meals, choosing coconut oil over polyunsaturated vegetable oils like safflower oil may be a simple way to boost your body’s nutrient intake for optimal health.

Just make sure that when you use coconut oil you are certain, like all your foods, you are getting the highest quality source possible.

Source: Dr. Mercola