Full Fat or Low Fat Dairy?

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If you are totally against low-fat dairy, it’s time to take a closer look at the research. After listening to this dairy debate and watching the finger pointing, I started searching through the literature for an answer to this question “does dairy fat increase LDL cholesterol and risk for cardiovascular disease?” Then I came to my senses. No one eats dairy fat. Unless you’re a food scientist, you aren’t separating the fat from milk or full-fat yogurt and eating it or adding it as an ingredient to your recipes. However, we do eat cheese and yogurt and drink milk. The array of compounds in each of these foods influences how they affect your cholesterol and risk for heart disease. So, I revised the question to: “how does full fat cheese, yogurt and milk impact cholesterol and risk for heart disease?”

Here’s what I’ll cover in this article:

  • Why people are up in arms about saturated fat – saying it is either good or bad;
  • How does full fat cheese, yogurt and milk impact cholesterol;
  • What should you do with this information?

Dairy Fat isn’t the Only Factor

The research on dairy generally follows the research on saturated fat: the replacement strategy matters. For instance, it isn’t a good idea to take cheese out of your diet and replace it with a highly refined carbohydrate (not a good move for blood fats). Butter isn’t better than liquid oil. Butter raises LDL cholesterol. Some research suggests dairy fat might raise the large, less artery clogging LDL cholesterol compared to small dense LDL. However, “less artery clogging” does not mean “not artery clogging” and this area of the science needs more work before we can draw firm conclusions. Also, there are a few differences based on the type of food (milk, cheese, yogurt, butter); aged cheese reigns.

dairy and cheddar cheese

-> Aged cheese does not raise LDL as much as butter (accounting for total fat in each). In fact, several studies show aged cheese appears to have a “relatively minor” impact on LDL cholesterol or no impact at all. This could be due to the calcium content, which leads to the excretion of some fat or, fermentation may have an effect. Aged cheese stands out in the research.

-> Yogurt appears to have less of a cholesterol raising effect than expected. However this research is inconsistent possibly due to differences in the type of bacteria in the yogurt (aka probiotics). I recommend choosing yogurt with “live and active cultures.”

– > Milk – when consuming the same amount of fat from whole milk or butter, both raise LDL to the same extent. Milk contributes substantially less total fat per amount consumed compared to full fat yogurt and butter. Cross-sectional studies suggest milk consumption doesn’t raise coronary artery disease risk, however, this may reflect lower total fat intake from milk compared to butter.

-> Cottage cheese –  this incredible food is oftentimes forgotten yet an excellent addition to your diet. I couldn’t find any studies on cottage cheese, however, the highest fat cottage cheese I could find  (4% milk fat) contained 5 g total fat per serving so we can expect the impact cottage cheese may have a lower impact compared to whole milk.

What Should You Do with this Information?

If your LDL is high, choose skim, 1% or low fat milk. Opt for a good quality yogurt with naturally occurring probiotics. As far as cheese goes – I’d take out all of the other offending foods and work on other aspects of heart health before ditching the cheese (unless your LDL is very high) and cottage cheese. However, always follow the dietary advice of your registered dietitian since there are many variables that should be taken into consideration.

What about the trans fats in dairy? They are good for you right? No. In large amounts, the trans fats in dairy have the same impact as those found in partially hydrogenated oil (not good for cholesterol, cardiovascular disease risk etc.). However, we don’t eat dairy trans fats in significant quantities (they make up very tiny amounts of dairy fat and beef fat).

Take Home Points

In general, dairy foods help lower blood pressure plus there is emerging evidence about the positive role dairy foods may play in metabolic syndrome. What about dairy fat? Consider the whole food and your diet overall so you can make the right choices based on your personal risk factors for cardiovascular disease. Also, keep in mind there are many factors that influence cardiovascular disease pathology, some of which are unrelated to cholesterol.

References

Tholstrup T, Hoy CE, Andersen LN, Christensen RD, Sandstrom B. Does fat in milk, butter and cheese affect blood lipids and cholesterol differently? J Am Coll Nutr 2004;23:169–76.

Hjerpsted J, Leedo E, Tholstrup T. Cheese intake in large amounts lowers LDL-cholesterol concentrations compared with butter intake of equal fat content. Am J Clin Nutr 2011;94:1479–84.

Biong AS, Muller H, Seljeflot I, Veierod MB, Pedersen JI. A comparison of the effects of cheese and butter on serum lipids, haemostatic variables and homocysteine. Br J Nutr 2004;92:791–7.

Nestel P. Effects of Dairy Fats within Different Foods on Plasma Lipids. J Am Coll Clin Nutr 2008, 27(6): 735S–740S.

Thorning TK et al. Diets with high-fat cheese, high-fat meat, or carbohydrate on cardiovascular risk markers in overweight postmenopausal women: a randomized crossover trial. Am J Clin Nutr 2015.

Labonté MÈ et al. Dairy product consumption has no impact on biomarkers of inflammation among men and women with low-grade systemic inflammation. J Nutr 2014;144(11):1760-7.

Sjogren P et al. Milk-derived fatty acids are associated with a more favorable LDL particle size distribution in healthy men. J Nutr 2004;134(7):1729-35.

Hodson L, Skeaff CM, Chisholm WA. The effect of replacing dietary saturated fat with polyunsaturated or monounsaturated fat on plasma lipids in free-living young adults. Eur J Clin Nutr 2001; 55(10):908-15

Soerensen KV et al. Effect of dairy calcium from cheese and milk on fecal fat excretion, blood lipids, and appetite in young men. Am J Clin Nutr 2014;99(5):984-91.

Grebe A, Latz E. Cholesterol crystals and inflammation. Curr Rheumatol Rep 2013;15(3):313.

 

 

Sourdough – Safe for Gluten Sensitivity?

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There’s something special about sourdough bread. Made through a slow process that begins with simple ingredients, warm water and flour, yeast and bacteria feast on the flour’s carbohydrate, producing carbon dioxide gas and bubbles that expand the dough. Each batch may tastes a little different depending on the flour and water used as well as the environment the starter is made in. My favorite sourdough bread, the kind that is made over the course of several days, has an alluring pungent, slightly sour taste. This long fermentation process leads to more complex flavors while also creating bread that is easier for those with gluten sensitivity to digest. I shared the science behind sourdough in this segment on Fox TV:

What is Gluten?

Gluten’s stretchy fibers give dough it’s rubberband-like elasticity allowing it to stretch when pizza dough is tossed in the air like a frisbee. Gluten-rich dough traps air and water during the baking process so bread rises with delicate ease, producing light and fluffy baked goods. Without wheat (and therefore gluten, which is produced when wheat flour is mixed with water), gluten free items require a blend of flours, starches and additives yet they still can’t replicate the texture of gluten-containing baked goods.

In people with celiac disease, an autoimmune digestive disease, repeated exposure to gluten damages villi, fingerlike projections in the small intestine that help us absorb nutrients from food. Over time, a decrease in nutrient absorption can lead to anemia, osteoporosis, miscarriages and other complications. The University of Chicago Celiac Disease Center website lists over 300 symptoms associated with celiac disease though anemia is the most common symptom in adults. The only available treatment is a strict gluten free diet – which helps reverse intestinal damage over time. Gluten sensitivity is not an autoimmune disease but instead a vague medical condition without a uniform definition or diagnostic test at this time. People with gluten sensitivity report various symptoms triggered by the ingestion of gluten-containing foods including abdominal pain, bloating, and constipation or diarrhea. Though gluten sensitivity is real, someone who thinks they have sensitivity may actually be reacting to something other than gluten (another protein or the starches – see below under Is it the Gluten?)

Sourdough bread

The Science behind Sourdough

Standard yeast leads to a fast fermentation process. This ramps up production speed and it is also foolproof so companies can produce batches of bread at warp speed. Sourdough bread is made slowly, over time, letting the yeast work it’s magic to deliver an array of flavors as well as bread that is easier to digest. In one study, sourdough bread made with selected sourdough lactobacilli and long-time fermentation resulted in bread with gluten levels of 12 parts per million (ppm), which qualifies for gluten-free (anything below to 20 ppm is gluten free). A long fermentation process allows bacteria and yeast adequate time to feed on proteins and starches breaking them down into more digestible parts. Yet sourdough also boasts a lower glycemic index than many other types of bread (including white bread) and therefore it doesn’t lead to a quick spike in blood sugar levels.

In 2011, a small study conducted in Italy tried giving volunteers with celiac disease a small amount of specially prepared sourdough bread. The bread was fermented until the gluten was broken down to more easily digestible parts. The subjects in the study reacted well to the sourdough, with no changes in intestinal villi and no detectable antibodies typically found when a celiac disease patient eats a gluten containing food. According to the study authors, the bread “was not toxic to patients with celiac disease.”

In another study, conducted over 60 days, baked goods made from hydrolyzed wheat flour, manufactured with sourdough lactobacilli and fungal proteases, was not toxic to patients with celiac disease. Though these studies are groundbreaking, it is far too soon for celiac disease patients to try this at home. For sourdough bread to be an option for those with celiac disease, a uniform production process would need to be established to ensure the end product is gluten-free.

For those with Gluten Sensitivity, Is it Really the Gluten?

Some people may experience bloating and flatulence in response to FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). FODMAPs are a type of carbohydrates that are not well absorbed in the small intestine and are present in bread along with a number of other foods (other grains, some vegetables and fruits). In some people the problem may be FODMAPs, not gluten. The long fermentation process reduces FODMAPs.

How to Make Sourdough at Home

Sourdough starter begins with flour and water that sits for several days while being fed intermittently with both flour and water allowing bacteria (lactobacilli) and yeast to grow and multiply creating live cultures. These microorganisms are what makes the dough ferment similar to the way milk ferments to become yogurt. Check out these recipes to make your own sourdough bread: Healthy Aperture, the Perfect Loaf.

If you run into problems making sourdough check out this page for troubleshooting.