Cheap to chic grass-fed beef

I've been fairly consistent about getting my weekday ground beef from the farmers market, but I wanted to get something different for saturday night.  I enjoy staying home for a nice saturday dinner for several reasons:  I have more control over the quality and quantity of my food, my girlfriend doesn't have to worry about gluten contamination, and I am more comfortable about eating medium-rare beef.  The latter is especially appealing after recently reading Fast Food Nation.  Eesh   But I have to make sure that I can out-do any steak house.

The more enticing cuts of grass-fed beef can be prohibitively expensive for a graduate student.  So to lower the cost, I was looking for something esoteric.  A shoulder clod* costs much less than steaks and is even cheaper than some other roasts, AND it happened to be on sale.  You just have to deal with the toughness of the cut.

Shoulder clod (far) and neck bones (near; a previous post...)

The entire goal of this recipe is to cook low-and-slow while still achieving medium rare, as both will improve tenderness.  As you'll see, wrapping the nearly finished roast in aluminum foil and a kitchen towel will allow the roast to finish cooking (medium-rare) and maintain enough heat to continue tenderizing the meat.  You'll sacrifice the texture of the crust, but it's well worth it.

Roast Shoulder Clod

1. Use a 2.5 lb shoulder clod roast.  Pat the roast dry and season liberally with salt and pepper, and a bit of garlic powder.  Cover tightly with plastic wrap and store in the fridge for 12-24 hours (although I only did 3!).
2. Preheat the oven to 225°F**, and let the roast rest at room temperature for 30 minutes.
3. Heat some beef tallow, or other high-heat cooking fat, in a heavy-bottomed pan. Sear all four sides of the roast.        
4. Place beef on a baking sheet and roast for 90 minutes, or until internal temperature reaches 135°F (for medium-rare).  Remove from the oven and wrap roast in heavy-duty aluminum foil, and then wrap in a kitchen towel.  Allow roast to rest like this for another 30 minutes. 
5. While resting, open a nice Cab that you essentially forgot that you had.  And fry-up some gluten-free squash blossoms, for good measure.

     5.  Slice as thin as possible.  Impossibly thin if you can...

Serve with some market vegetables.  Make sure to arrange food in a pretentious "man, I gotta' blog about this meal" sort of way.   

*From what I can tell, the shoulder clod that I bought was only part of a true shoulder clod.  Technically, beef clod refer to an entire beef shoulder.  Similar to the Boston Butt of a pig.

**I'm aware that it is generally a poor idea to rely on the oven in the summer, especially if you don't live in mild California.  This should work just as well on a grill or in a smoker.  However, if using a grill, roast meat on the unlit side of the grill and do your best to maintain this low temperature; this will mimic an oven.  

This post was submitted to Food Renegade's Fight Back Friday

Food Science: What happens when you rinse kefir grains?

So, ignore the name of my blog for this post.  That's right.  It's time for some food science.  But in my defense, it involves traditional food (kefir) and good ol' falsifiable science.  That's right.  I did a an experiment to determine whether or not one should rinse kefir grains before adding them to a fresh batch of milk.

Kefir is not a popular food, at least not compared to its yogurt-y cousin.  So when you decide to go out and make it on your own, you have to rely on what you can dig up on the internet.  And true to the internet's reputation, you can find any possible answer for whatever question you are asking.  One simple question that I had was whether or not I should be rinsing the grains between batches.  The information I received with my grains said I should not rinse them.  However, Nourishing Traditions seems to suggest that they should be rinsed.  There was only one way to find out.  I hypothesized that rinsing the grains would blunt their capacity for producing kefir, and therefore produce a milder kefir.

Fig 1.  Separated and weighed to 10 grams

Methods

The grains were rinsed and randomized.  Two groups, each weighing 10 grams (g) and containing 18 grains (Fig 1), were formed.  Most batches were made with 8 ounces of organic pasteurized whole milk; the last couple of batches were a bit over 8 ounces to accommodate the increased fermentation.  Fermentation was 12-14 hours per day. Clean jars were used each time.

Fig 2.  Kefir preparation.  Clean jars, 8 oz. milk, cover with paper towel. 

The time and temperature were not always consistent.  However, because the jars were adjacent to each other at all times, any day-to-day variation would affect each group equally, and would therefore not bias the results.  The only difference between the groups was that the experimental (washed) group was rinsed under cold tap water in a stainless steel strainer until curds were removed, roughly 10 seconds.  The control group was simply placed in a new batch of fresh milk.  The experiment ran for 11 days, and on the 7th and 11th days, both groups of grains were washed and weighed, and the two different batches were tasted by a blind taster a.k.a. the girlfriend.

Results

Both groups increased in weight at the same rate.  However, the grains in the unwashed group were more dense than the washed group on day 7 (0.67 g/grain vs. 0.48 g/grain) and on day 11 (0.74 g/grain vs. 0.51 g/grain).  Thus, rinsing reduced the density of the grains by 30%, and produced many small grains (Figs. 3-5).

Fig 3. Unwashed (left) and washed (right) groups at the end of the study.

Fig. 4 Results of control (unwashed)

Fig 5.  Results of experimental (washed) group.

Tasting results were consistent between the 7th and 11th day.  Both batches of kefir reportedly tasted as kefir should, and both batches were similarly thick, both in the glass and in mouthfeel.  However, the unwashed kefir was "definitely more sour."  Furthermore, the washed kefir had a lighter effervescence with smaller bubbles and "a more full kefir taste."  The unwashed group appears to ferment faster, as there was usually more whey present (Fig 6).

Fig 6.  The unwashed (left) was usually more fermented.

Discussion

This experiment demonstrates that rinsing kefir grains between batches produces more and smaller grains than when grains are left unwashed.  Furthermore, these rinsed grains tend to produce a milder kefir.  While I can surmize that this occurs because the unwashed grains produce kefir at a faster rate (and therefore make a more kefir, kefir), that will require another experiment.

I'm definitely confident in these results, but I would love to hear other peoples' experience with washing their grains.  The results might have been more dramatic had I not rinsed and weighed the grains mid-experiment, but then again, this added a bit of reproducibility within the study.  Unfortunately, I was not blinded to the treatment group.  And come to think of it, the kefir wasn't blinded with a placebo.  I already anthropomorphize my kefir grains enough as it is, but perhaps they knew what group they were in...

So, what can we take away from this bit of food science?  There are likely many recommendations for treating kefir grains because there is no obvious best way.  While I would argue that the density produced by leaving the grains unwashed is evidence of "healthier" grains, if you prefer the taste of a mild kefir, then you would be better off rinsing them, at least occasionally.  Or, as I've started doing, rinse the grains on warmer days or when you might make it home late and risk over fermenting the kefir.  Either way, it's between you and your kefir.

Now, it's time for a kefir smoothy.  Theory into practice, I suppose.  Cheers!

This post is shared on Real Food Whole Health's Traditional Tuesdays.

Fermenting isn't just for dairy: Curtido, or Latin "sauerkraut"

As I mentioned in my kefir post, once you start fermenting dairy, you've entered into whole other world of local-hippie-whole food.  Fermenting a few veggies to create the Latin relish curtido was the next logical step.  From what I can tell, the recipe I used most closely resembles the Salvadoran version of this common condiment.  I adapted the recipe from Nourishing Traditions by Sally Fallon.  Who would have thought fermenting your own veggies would be so easy?  Again, as far as I'm concerned, the jury is still out on whether probiotics are a panacea or not, but at least they taste darn good.

Salvadoran Curtido (a la Nourishing Traditions)


1.  Shred 1/2 to 3/4 of a full green cabbage, grate about 1 cup's worth of carrots, and finely slice half of a large red onion from pole to pole.  Combine in a large bowl.

2.  To the bowl of veggies, combine a tbsp of kosher salt, a 1-2 tsp of dried oregano, and a big pinch of crushed red pepper.  Add 4 tbsp of whey (I strained out some from an over-fermented batch of kefir).

3.  Do some light stretching, then smash all the veggies to extract their water.  It should take about 10 minutes worth of smashing.  You could use a meat tenderizer, or do like I did, and grind them with a pint glass.  I believe Alton Brown would call that a multi-tasker.

After ten minutes, and switching arms a few times, it should looks like this:

4.  Transfer the veggies and liquid into a very clean quart-size jar with a lid.  Pack down the veggies so that they are completely submerged by the fermenting liquid.  This is important, because from what I've read, failure to do this may lead to spoilage (growth of the bad rather than the good bugs).  Make sure that there is at least an inch from the top of the jar to prevent explosions.  Cover and leave at room temperature for 72 hours, then transfer to the fridge.  The curtido will improve with time in the fridge.  I finished mine within two weeks, and it was great until the end.  Not sure how much longer it would last.

I let mine ferment with its friends...

When it's finished, it will look something like this:

Tangy, flavorful, and spicy.  A bit too strong on it's own, but it is incredible with the richness of meat.  Especially with my almost-daily burger:

Unintentional paleo...

Here's to good bacteria, in milk and in veggies.

Frittata Dinner

I've been a bit slow on my food posting the past couple of weeks.  I've been eating plenty of good food, but just haven't gotten around to sharing it.  Here's another farmers market dish that is also low in  carbohydrates: market vegetable and cheese frittata.  It's rich enough for a meatless meal.  The recipe was inspired by a dish at the Food Network.

Market Vegetable and Goat Cheese Frittata
Preheat oven to 350 degrees.  You will need a 10-12 inch ovenproof skillet.


1.  Whisk 8 eggs with 2 tbsp heavy cream and a dash of Worcestershire sauce.  Add a big pinch of kosher salt, and some fresh pepper.

2.  Wash and cut 2 cups of fresh spinach.  Slice 2 scallions.  Crumble 5 ounces of fresh goat cheese.  Prepare or grab 1/2 cup of shredded parmesan cheese.

3.  Sauté about 15 thin asparagus stalks (about one bunch from the market) in 2 tbsp of olive oil for 2 minutes.  Remember to cut the asparagus so that you reserve the tenderest part.  Season while cooking.

4.  While the asparagus is sautéing, combine spinach, scallions, and cheese into egg mixture.  Stir to combine.  Remove pan from heat, and add egg-veggie mixture.  Place on middle rack of the preheated oven.  Bake for 20 minutes.

5.  Have a light summer cocktail on the porch.  (White wine, shot of Aperol, slice of lime, all over ice)

6.  The frittata is finished when the middle is just-cooked and the edges are lightly browned.  I believe it is traditional to flip the frittata out of the pan and onto a plate, but hey, it's good no matter what side you call top.

7.  While the Frittata is cooling, prepare tomato salad for topping.  Slice two ripe tomatoes and dice 2-3 tbsp of garlic chives.  Combine with a bit of olive oil, lime juice, and a pinch of salt and pepper.

8.  Serve a slice of frittata and top it with the tomato salad.  Serve with a side salad; we chose caesar.

A great way to enjoy some market eggs.  Eggs that come from chickens that do things like this:

Fight Back Fridays submission - On Cohorts and Coffee

I want to share my On Cohorts and Coffee post at Food Renegade's Fight Back Fridays.  While my post may be non-traditional for Fight Back Fridays, I hope that I can share my insight into the methodology of nutrition science rather than the results of nutrition science.

Since that post was from Tuesday, this is simply a Friday post to link back to the older post.  I'll be sure to post on Friday next time I participate!

On Cohorts and Coffee

Coffee beans, courtesy Elvis John Ferrao on Flickr.

Are you a big coffee drinker?  How many cups per day?  2? 4?  Well, if it's six or more, and if you're a man, then you may be lowering your risk of lethal prostate cancer.  That's great news for those of us who liberally indulge.  But if you don't drink coffee, should you?  Headlines that tout the benefits of individual foods are common.  Many of these findings are produced by observational epidemiology, so making an informed decision about integrating these foods into your diet requires an understanding of how these studies are designed, their strengths, and their weaknesses.  As in the aforementioned headline, much of the science of nutrition is derived from cohort studies.

A prospective cohort study, or longitudinal study, is an epidemiological study that defines two or more groups of people with various exposures (e.g hormone replacement therapy, coffee drinking), and then follows this cohort to measure any differences in outcomes (disease) between the groups in order to infer a causal association (see figure below).  Ideally, researchers ascertain a breadth of exposures and characteristics to discover associations and to improve the validity of such discoveries.  If an exposure is rare in the general population, a "special exposure cohort" can be used to follow a uniquely exposed group, such as vegetarianism in Seventh-day Adventists, and compare the special group's outcomes to a similar non-exposed group or the general population.  There are a few major prospective studies in nutritional epidemiology that warrant some attention.

 Source: Wikipedia.  Note that the investigator ascertains the exposures (black/white) prior to the unknown outcome.

One of the most influential diet studies is the Nurse's Health Study.  This study is technically composed of two phases, NHS I and NHS II.  NHS I began in 1976 to identify potential long-term complications of oral contraceptives that many women had begun to take.  It was later expanded to include diet and quality of life data.  NHS  II began in 1989 and recruited younger nurses for the purpose of collecting data on oral contraception, diet, and lifestyle factors that began earlier in life.  Major findings from this study include: smoking has a strong positive assocation with cardiovascular disease that reduces with smoking cessation, obesity increases the risks of several chronic diseases, and a Mediterranean-type diet appears protective.  However, the spurious idea that hormone replacement therapy would prevent coronary heart disease in all post-menopausal women was also produced by this study.

The Health Professionals Follow-Up Study (HPFS) began in 1986 as the male complement to the NHS.  And it produced the coffee-prostate cancer study above.  It is comprised of roughly 51,000 non-medical doctor health practitioners; over half of them are dentists and the vast majority are white.  Here is an example of the long form survey sent to participants.  Both the NHS and HPFS recruited motivated healthcare practitioners because this population is expected to accurately report disease outcomes and has the occupational commitment to maintain follow-up.  In fact, the NHS has retained a 90% response rate.

The Eurpoean Prospective Investigation into Cancer and nutrition, or EPIC, is a European equivalent.  This study has recruited over half of a million people from ten European countries, and studies the general population rather than healthcare practitioners.  Here's a neat infographic depicting the reported diet of "health conscious" and general population groups; it's a nice example of how types of people do not just aggregate around one food choice or the other, but rather a whole pattern of eating.

Cohort studies can be prohibitively expensive and are generally restricted to relatively common diseases or outcomes. But they offer substantial benefits over other types of observational studies for establishing a causal assocation.  If putative exposures and outcomes are measured at the same time, such as in cross-sectional studies, one cannot say with absolute certainty which one preceeded the other.  Cohort studies are better capable of  determing this information, or more technically, establishing the direction of causality.  Additionally, cohort studies often use real-time medical records, physical examination, or biological tests, and sometimes all three, to provide valid measurements of the exposures rather than relying on subjective recall.  However, unlike randomized controlled trials, the exposure status is chosen by the subjects and not the researchers.

In a prospective cohort study, the investigator ascertains the exposure status of the subjects and then groups them accordingly.  If science was easy, then these populations would just so happen to be the same with the exception of the exposure of interest.  But science can be cruel, and there is myriad reasons why individuals "choose" different exposures, which biases the results.  In our coffee study, it is possible that men who were developing lethal prostate cancer avoided coffee due to subclinical symptoms related to the impending prostate cancer diagnosis, which would bias cancer prone individuals away from coffee exposure.  This is called self-selection bias and can only be avoided by assigning exposure.  The investigators attempted to correct for this reverse causation by doing a sub-analysis with urinary symptoms to ensure that these type of symptoms were not associated with lower coffee consumption.  But such a bias could still have occurred from an unknown non-urinary symptomology or "drive" for cancer prone men to drink less coffee.   As such, the causal association between exposure and outcome from a cohort study is only inferred (e.g "heavy coffee consumption protects against lethal prostate cancer"), and can technically only be interpreted as "people who choose, or are otherwise driven by unknown factors, to consume large amounts of coffee tend to have a lower risk of lethal prostate cancer."  And then there's the issue of what we failed to measure.

The second major problem with the validity of cohort studies is the effect of confounding variables.  Because the groups are not randomized, the population with the exposure of interest may also have another exposure that associates with the outcome.  The classic example is the apparent positive association between coffee consumption and lung cancer.  This association is entirely explained by the fact that coffee drinkers also tend to smoke.  In the coffee and prostate cancer study, the invetigators made a Herculean effort to control for confounding by adding numerous potential confounders into their risk model.  These included: race, BMI, smoking, multivitamin use, PSA test history, and many more for a total of seventeen variables.  While adjusting for more and more confounders does enhance the validity of the association, remember that this type of manipulation is limited to "prostate cancer risk factors previously identified in this cohort and in other studies."  We cannot know what we have not measured, and it is always possible that there is at least one unknown variable that confounds our association of interest.

For what it's worth, I have a soft-spot for cohort studies.  The idea of a "natural experiment" is somehow quaint and very appealing.  They offer a lot to validity over other types of observational studies, but they always have important flaws, namely selection bias and potential confouding variables.  At the risk of pessimism, good science requires that we highlight the flaws of each experiment.  Read the headlines (and preferably the whole article!) with a critical eye.  Take note of the study design, and always ask how it fits into the greater scheme of the evidence.  As the authors concluded, "it is premature to recommend that men increase coffee intake to reduce advanced prostate cancer risk based on this single study."  Given the nature of this study, I will remain skeptical that coffee is therapeutic, although I am more confident that it is harmless.  But keep in mind that my opinion is heavily biased, as I've invested too much into my habit to stop any time soon.

Everything but the ketchup...

I took this long holiday weekend to hit the farmer's market hard and make a mess in the kitchen.  The Saturday morning market was hot and busy.  And it didn't help that I was lugging around an entire flat of strawberries (you'll see why below).  After the market, we settled down for the All-American classic: hamburgers.  We did them protein-style with grilled onions, avocado, and pepper Jack cheese.  And we celebrated the coming of the fig season with fresh figs topped with goat cheese and honey.  And yes, I do celebrate fig season.  And to celebrate America this weekend, we enjoyed an entire meal from the local farmers who grew it.  Well, everything but the ketchup.

From now on, I call it the "Farmer Burger"

Figs and goat cheese

Figs with goat cheese and honey

1. Choose black mission figs that are extremely soft, and slice them in half
2. Top with fresh goat cheese
3. Drizzle with honey (we used avocado honey, which was almost savory - much more interesting than the store bought)
4. Sprinkle with almond slivers, if on hand.  

And for dessert later that night:

The gluten-free crust is under there somewhere...

Home-made gluten-free strawberry pie.  In no way was this low-carb, but we wanted to celebrate with an American classic.  Although I am generally in a quandary regarding strawberry pie, which has taken me to deep philosophical thinking about the fundamentals of pie that I can elaborate on at some other time, I was very pleased to make it from scratch.  The glaze definitely didn't look as pretty as the one from Marie Callender's, but since it was made from only puréed strawberries, sugar, and pectin, it was one of the freshest tasting pies I've ever had.  And we got to take the leftovers to watch the fireworks tonight.

Happy Fourth!

How I make Kefir

You didn't think that I would write an entire post on kefir without sharing how I make it, did you?  From what I've been able to find, the fundamentals of making kefir are universal, but everyone has their own take on the proportions, time, and processing.  Here's how I've been doing it.

1.  Remember, this is a continual process from the previous batch of kefir.  After straining the kefir, I set the grains aside and thoroughly wash the glass jar I used for fermentation.  I use about two tablespoons of kefir grains for every 12-14 ounces of milk, which is more concentrated than typically called for.

I don't wash the grains, but some people do.  Over several batches, the grains will accumulate a polysaccharide gel known as kefiran, and many writers purport that this enhances the kefir making process - I'll talk about this in a later post.  

Kefir grains

2.  Place the kefir grains into a large jar and add 12 ounces of whole fat milk.  I add a couple tablespoons of cream for good measure.  I use this as an afternoon snack, so it needs plenty of calories to hold me over.

I do my best to buy organic milk, especially if I am more confident that the cows are mostly grass-fed.  Remember, organic cows can still be on a feedlot.  I try my best to use the pasture-based animal products since it's better for the cows and doesn't perpetuate the over-use of antibiotics in cattle feed.  And grass-fed organic cow's milk is probably somewhat more nutritious than conventional grain fed cow's milk.  After all, cows evolved eating grass and not corn.  However, the major problem with organic milk is that it is usually ultra pasteurized (UHT) rather than conventionally pasteurized.  Thus, it tends to have a cooked taste.  I was pleased to find conventionally pasteurized organic milk at Sprout's.  This particular dairy does not have to rely on excessive pasteurization to prevent early spoilage because it is local and travels a shorter distance.   

Bath-time for the grains

Organic and pasteurized, not UHT.

3.  Allow the mixture to ferment for roughly twenty-four hours at room temperature.  Cover with a towel.  Keep in mind that the ambient temperature will change the rate of fermentation.  Hotter days/nights will speed up the process.

Kefir-ing.

4.  The kefir is ready when it has small pockets of clear-yellow whey and small bubbles.  It smells of yogurt (due to the lactic acid producing bacteria) with a hint of sourdough bread (due to the yeast).  Pour the mixture through a strainer and bump the shaker with your hand until you are left with kefiran-covered kefir grains.

Notice the small bubbles at the surface.

Strain into a large-ish bowl to prevent a mess.

5.  Pour the kefir into a jar and let it chill in the refrigerator.  It will continue to ferment in the refrigerator because of the residual microorganisms, but it will be much slower at this lower temperature.  I like to drink it straight, especially with a touch of sweetener.  But there are many other things you can do with it...

Kefir goodness

Introducing Kefir

Kefir

After coming across various blog posts on fermented dairy (yogurt, kefir, cultured butter), I was intrigued.  I placed an order for kefir grains from The KefirLady and started a batch as soon as they arrived in the mail.  Once you start fermenting your own dairy, you've crossed into a another world of hippie-locavore-homecooking that you cannot return from.

Kefir is simply fermented milk.  Its origins have been traced to Caucasus, where the Muslim population regarded kefir as a gift from Allah.  The fermentation is achieved by inoculating a container of milk with a combination of bacteria and yeast, collectively known as kefir grains. The grains metabolize the nutrients in the milk - the lactose and some fatty acids - and in-turn produce carbon dioxide, lactic acid, and small amounts of a host of other compounds, including ethanol.  These benign microorganisms out-compete and actually fend-off pathogenic bacteria, thus preserving the milk without refrigeration.  Kefir is unique because it contains both bacteria and yeast, unlike yogurt which only contains bacteria, and because the grains are re-used again and again with each new batch.  Similar to other fermented foods, kefir is considered a probiotic.

Kefir grains

A probiotic is defined as "microbial cell preparations or components of microbial cells that have a beneficial effect on the health and well being of the host."  Many of the purported health benefits of fermented products are commonly attributed to improved gut health and modulation of the immune system (via the gut), although some have investigated possible anti-cancer properties. While everyone is familiar with probiotics because of the yogurt craze, the idea that fermented foods are healthful is not new.  As implied above, the people of Caucasus had much appreciation for kefir.  But despite the precedence, we cannot yet call probiotic foods a panacea. 

The Cochrane Collaboration has found no benefit in probiotics for inducing remission or maintaining remission in Crohn's disease, which perhaps argues against how strongly probiotics can modulate the immune response.  In regard to general gut health, Cochrane did find limited evidence for reduced c. dificile re-infection and minor improvements in childhood diarrhea.  These trials commonly used isolated  probiotics, so perhaps whole food probiotics are more beneficial.

There is some evidence that yogurt and the lactobacillus bacteria it contains can improve gut health in humans.  However, the most compelling evidence seems to be in regard to relieving constipation, particularly in children and women.  From what I can gather, lactobacillus containing yogurt does appear to relieve constipation, although not necessarily with the consistency asserted by advertisments.  To be sure, my cursory review of the literature does not warrant a definitive assessment for or against the benefits of probiotic foods, but I think there are a few things to keep in mind.  

The whole area of probiotic research suffers from inconsistant trial design, inconsistent use of bacteria and probiotic sources, and trouble defining exactly what "gut health" is.  The role of gut bacteria and health is compelling, but our understanding is still in its infancy.  We know that illness is associated with different gut microflora, such that obese children and those with Crohn's disease have different gut microflora composition than normal controls.  And as I learned from this past weekend's American Diabetes Association conference, these microflora are partially malleable e.g bariatric surgery changes the prevalance of different bacteria within the same individual.  However, we still do not understand what these associations and changes mean.  And while this research will likely provide improved treatment for gut disorders and diseases, we are still unsure how readily one food (kefir, yogurt, fermented vegetables) will change our gut bacteria and subsequently our health.  But I still think trying kefir is worthwhile.

From my experience, and I know that I am not alone, conventional medicine does a poor job with general gut health.  Conventional medicine clearly has a grasp on serious digestive diseases such as colon cancer, but more nuanced problems, such as food intolerances or sensitivities, usually evoke eye-rolling or a psycho-somatic diagnosis.  The diagnosis-by-exclusion Irritable Bowel Syndrome is likely a symptom of this general ignorance.  Although to be fair, I am not convinced that alternative medicine understands gut health as much as it purports to.  So given that fermented foods are both traditional and whole foods (avoid sugar containing yogurts!), and given their potential benefit, I think they are absolutely worth trying.  And because I make the kefir myself, I know that it has the probiotics that it is supposed to.  And if it is nothing but nutritional mysticism, at least it is low carb mysticism (the bacteria eat the milk sugar so that I don't have to).  And hey, instead of a cat to keep me company, now I have kefir grains to come home to.