The Fat Truth Behind the Dairy Weight Loss Miracle: MUFA and PUFA Impair, Saturated Fat and Plenty of Micronutrients Drive Full-Fat Dairy-Powered Fat Loss.

Image 1: Kids who drink more milk, tend to be leaner... and that despite (?) the fact that this stuff comes out of an animal and is full of bad cholesterol and fat - outrageous ;-)

Plenty of interesting news, lately, so this one - just like the recently released hypertrophy / hormone correlation study by Stuart Phillips, about which I have been talking in yesterday's installments of the Intermittent Thoughts got somewhat delayed. With the Christmas holidays and the approaching and all those New Year's weight loss resolutions (I would prefer the term "fat loss resolution", though ;-) already on your mind, I do yet think that it is about time to break the news on the "fat" reason for the purported beneficial effects an increased consumption of dairy products during periods of caloric restriction appears to have on weight and more specifically body fat loss (Linn. 2000; Peirara. 2002; Shahar. 2010).

Dairy, calcium or simply the right macronutrient composition?

The scientific results I am going to present are taken from a study that was published in the Journal of Nutrition and Metabolism a few weeks ago (Smilowitz. 2011). In a randomized, placebo-controlled study Jennifer T Smilowitz and her colleagues from the USDA-funded (keep that in mind, when interpreting the results, or rather the scientists interpretation of the latter ;-) Western Human Nutrition Research Center assigned their 62, against the background of the rampant obesity epidemic, only slightly overweight young subjects (mean age: 25y; BMI ~28) to a calorically restricted diet (-500kcal) that was specifically designed to "provide comparable levels of macronutrient and fiber, to approximate the average consumption in the US" (35% fat, 49% carbohydrate, 16% protein and 2-3g fiber), which contained either

• 0-1 servings of dairy, with 500mg dietary calcium (from the whole diet) + placebo,
• no dairy (still 500mg calcium from diet), 900mg of supplemental calcium carbonate, or
• 3 servings of dairy, with 1400mg of dietary calcium (from the whole diet) + placebo

Thusly, the study basically mimicked, what would happen if you told the average American to just keep their usual sedentary life-style (the subjects were instructed not to start to exercise or anything like that) and either just reduce his caloric intake by 500kcal, to do the former and to make sure to have three servings of dairy per day, or to just take an additional "healthy" calcium carbonate supplement.

Eat dairy + whatever you want and lose weight?

Now, interestingly, the subjects were not only free to chose whether they wanted to consume the dairy from low or normal fat cheese, milk and/or yoghurt, they were also relatively free as far as the rest of their dietary choices were concerned so that the detailed analysis of their food-logs allowed for conclusions to be drawn that went beyond the initial scope of the study... but let's take one thing after the other.

Figure 1: Dietary intake (macronutrients in kcal/day) of the subjects before and at the end of the 12-week study period and relative changes in carbohydrate, protein and fat intake (data calculated based on Smilowitz. 2011)

If you take closer look at the analysis of the dietary records the subjects had to keep, you will notice that the minor differences in the dietary prescriptions induced quite profound changes as far as the macronutrient composition of the respective diets was concerned. While the subjects in the non-dairy groups, regardless of whether they received a calcium supplement or placebo, cut back on all the three major macronutrients, the requirement to incorparate three servings of dairy into their meal-plan, alone appeared to suffice to keep the protein intake of the dairy group at a reasonably high level (~72g; which would be 0.96g/kg body weight). The protein intake of the two non-dairy groups, on the other hand dropped to 57g (0.75g/kg) and 54g (0.7g/kg) for the calcium and placebo supplemented groups, respectively.

Figure 2: Changes in body composition and measures of insulin sensitivity after 12-weeks on the high dairy, calcium supplemented or placebo supplemented diets (data calculated based on Smilowitz. 2011)

In view of the facts that the subjects had to stick to the calorically restricted diet for 12 weeks, it should not surprise you that all of them lost a statistically significant amount of body weight (cf. figure 1) and improved their insulin sensitivity (as indicated by reduced insulin levels and HOMA-IR values).What should yet strike your eye are the increased reductions in body fat and waist circumference and the greater increase in lean mass-% in the high dairy group. Now, you will probably assume that this was a result of the higher protein intake, and that may in fact have been the case, as one of my beloved model calculations by which scientists "adjust" their data for whatever they want (usually until the result is in accordance with their hypothesis ;-) revealed that

Dairy product consumption was found to be significantly associated with reduced WC [waist circumference] and %BF [percent body fat], however, these relationships were no longer significant after adjustment [my emphasis ;-] for protein and energy intake and physical activity.

Figure 3: Scatterplot of the partial correlations between reported 12-week mean dietary fat intake expressed as % of total energy and changes in lean body mass (LM) and body fat % (taken directly from Smilowitz. 2011)

Assuming that this "adjustment" yielded valid results it is all the more interesting what a subsequent analysis of the "adjusted" data revealed:

When expressed as a percent of total energy, dietary fat composition was correlated with changes in anthropometrics. Reported MUFA at 12 wk was inversely and positively associated with changes in % LM and % BF, respectively.

Or, in the words of the layman: The greater the relative monounsaturated fatty acid (MUFA) content of the subjects' diets, the more lean mass was lost and the more body fat was retained during the study period (cf. figure 3). Similarly, a higher intake of polyunsaturated fatty acids (PUFA) was associated with lower reductions in waist circumference, and while  the scientists claim that the n3:n6 ratio did not matter, it should make you wonder if it could actually be coincidental that the n6:n3 ratio in the dairy group was 6.6, while the ones in the calcium and placebo groups were 8.7 and 7.9, respectively.

And what about saturated fats? 

Moreover, the USDA scientists mention only "in the small print" that most fundamental (and statistically significant) distinguishing feature of the dairy group, who unquestionably had more favorable weight loss results despite an overall greater caloric intake, was (and I am quoting this from the paper) "a significantly higher intake of SFA [saturated fats] and lower intakes of MUFA and PUFA compared with the calcium supplement and placebo groups". Now, guess where this "bad" saturated fat came from? Well, probably from full-fat dairy! And guess why those "good" MUFAs and PUFAs were missing from the diets of the high dairy group. Well, probably because the subjects ate less "healthy vegetable oils"... ah, and did I already mention that the dairy group also ingested disproportionally (relative to their caloric intake) higher amounts of biotin, vitamin B12, vitamin D and - God forbid! - cholesterol?

Image 2: Even if you like animals, eating their eggs and full-fat dairy products won't hurt them.

So, while the scientists do their best to conceal that all those "bad things", like a high protein intake and nutrient dense real non-processed animal products with their original (saturated) fat, cholesterol and micronutrient content left untouched, are the true driving forces of successful weight loss (and, you bet, also maintenance), I am quite confident that you, as a diligent student of the SuppVersity, would not have needed the doctored... ah, pardon me, ... I obviously meant the well-adjusted results of this study to know that. After all, you are probably just enjoying a rib-eye steak with some delicious melted butter from grass-fed cows, right?

Vitamin B12 - A Nutrition Guide for Vegetarians & Vegans: From Nori to Mushrooms, Omnivores Can Benefit, Too!

With 77µg per 100g of the Nori leaves in the wrapping sushi makes an excellent B12 source, even if you stick to the vegan, no tuna version ;-)

If this is not your first visit to the SuppVersity you will be aware that I am not a exactly a proponent of vegetarianism let alone vegan dieting. Just like any other severely restrictive diet people who don't eat animal products are at an increased risk of nutrient deficiencies.

For vegetarians and even more so for vegans, it is not exactly easy to cover their daily requirements of vitamin A, vitamin D3, iron, cholesterol (yes, cholesterol is an essential nutrient!), n-3 polyunsaturated fatty acids and saturated fats. The most urgently needed nutrient for the average vegetarian / vegan dieter, however is vitamin B12, or cobalamin, as scientists say.

Actually dairy happens to be an excellent B12 source. Why not become lacto-vegetarian?

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Is There a "Fat Advantage" for Dairy Lovers

Want B12, But Hate Meat? Drink Milk!

Vitamin B12 is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins. It is normally involved in the metabolism of every cell of the human body, especially affecting DNA synthesis and regulation, but also fatty acid metabolism and amino acid metabolism. Neither fungi, plants, nor animals - including humans - are capable of producing vitamin B12. Therefore a sufficient intake of vitamin B12 is essential for optimal health.

Even in omnivorous humans, vitamin B12 deficiencies are frequent (Stabler. 2004). Among vegetarians and specifically vegans, it is yet rampant (Pawlak. 2013; Pawlak. 2014).

Figure 1: Reliable data on B12 levels is scarce. Based on surrogate markers and B12 deficiency symptoms scientists are still certain that "B12 deficiency as a worldwide problem." (Stabler. 2004) - one vegetarians are particularly susceptible to.

In the latest review by Pawlak et al. who included only studies that assessed serum vitamin B12 an reported actual percentages of vitamin B12 deficiency (40 studies total)...

• the deficiency prevalence among infants reaches 45%,
• the deficiency among the children and adolescents ranged from 0 to 33.3%, and 
• the deficiency among pregnant women ranges from 17 to 39%, dependent on the trimester

Adults and elderly individuals who follow a vegetarian lifestyle had a deficiency range from 0–86.5%. In general, higher deficiency prevalence was reported in vegans than in other vegetarians.  Accordingly, Pawlak et al. conclude that...

"[...]with few exceptions, the reviewed studies documented relatively high deficiency prevalence among vegetarians. Vegans who do not ingest vitamin B12 supplements were found to be at especially high risk." (Pawlak. 2014)

For vegans, specifically, the scientists recommend the routine use of vitamin B12 supplements to ensure adequate vitamin B12 intake and point out that "[v]egetarians, regardless of the type of vegetarian diet they adhere to, should be screened for vitamin B12 deficiency." (Pawlak. 2014)

Why is it so difficult for vegetarians and vegans to meet their requirements?

The Institute of Medicine’s recommended dietary allowance (RDA) of B12 needed to meet an adult’s requirement as 2.4mg per day. B12 is synthesized only by microorganisms, and this is why natural food sources of B12 are limited to meats and foods of animal origin.

 "Clams and beef liver are the highest sources of B12, containing about 84 and 71mg of B12 in a 3 oz serving (USDA. 2011). The amount of B12 found in a chicken varies from about 3.3mg in the entire chicken liver to 0.03mg in achicken’s neck. Pork contains between 0.3mg of B12 in each sausage patty to about 11.4mg in pork liver. 6 The content of B12 in fish ranges from about 9mg in one half of a fillet of sockeye salmon to about 0.5mg in a 3 oz serving of yellow fin tuna." (Pawlak. 2013)

Needless to say that a vegetarian or vegan person mustn't eat any of the aforementioned "good" B12 sources. The question is thus: Where can a vegan or vegetarian get his B12 from?

Diagnosis of low B12 levels is tricky! The most commonly used cobalamin essay has a sensitivity of "only" 62.6% and produces 22%+ false positives. An often-used alternative, the holotranscobalamin essay is a tad better, but with a sensitivity of 64.7% and 18.4% false positives, not exactly accurate, either (Carmel. 2013). Until now no 100% reliable test is available and studies like Salomon (2005) show that patients with "normal" plasma cobalamin levels, but symptoms vitamin B12 deficiency improve after treatment with the vitamin.

In view of the fact that the name of this website contains the word "supplement", the most obvious and probably safest source are supplements. In that, it's important to point out that not all supplements that promise to solve the vegetarian B12 problems will actually deliver.

Fourteen years ago, Micheal S. Donson tested the efficacy of sublingual cobalamine tablets, nutritional yeast, and probiotic supplements in a group of Hallelujah dieters and other raw-food vegetarians and found that only the former two, i.e. the sublingual cobalamine tablets and the nutritional yeast that contained 5µg of cyanocobalamin per tablespoon brought his subjects' depleted B12 levels back into the normal range. The probiotic supplement, on the other hand, was useless (Donaldson. 2000).

For patients with insufficient intrinsic factor production oral supplements are not suitable, though. For them, only injectable vitamin B12 will reliably bring their levels back up (Katz. 1972). People with low stomach acid, which often occurs with aging, as well, and people with gastric bypass (Smith. 1993) have similar, but less pronounced problems to cover their B12 requirements from oral sources (dietary and supplemental).

Now, supplementation and injections are nice, but isn't is possible to get your B12 from foods without having to eat meat and animal products?

In general, it is possible, but there is one major problem: The total content and bioavailability of vitamin B12 in food sources vegetarians and vegans can eat is comparably low.

Table 1: Content and bioavailability of selected "good" dietary sources of vitamin B12 (Watanabe. 2007)

If you take a look at the data in Table 1 you will see that the only source that can keep up with fish and meat are algae. Chloeralla in particular is an excellent source of dietary B12 for both vegetarians and, if I didn't miss yet another stupid dogma, vegans, as well (Watanabe. 2007).

In a previous study, Watanabe et al. (2002) have found that chlorella tablets, but not spirulina, which contains mostly pseudy vitamin B12 is a suitable source of vitamin B12 for man (and woman ;-).

In a more recent overview of vegetarian and vegan B12 sources, the researchers from the United Graduate School of Agricultural Sciences at the Tottori University in Japan (Watanabe. 2014) compiled a comprehensive overview of suitable B12 sources which includes...

• 

  Are "organic" vegetables worth it? Find out in a previous article.

  Vitamin B12-Enriched Beans and Vegetables Produced Using Organic Fertilizers or Hydroponics -- Previous research has shown that you can significantly increase the B12 content of spinach by adding an organic fertilizer such as cow manure. Practically speaking this is an increase to to approximately 0.14 μg/100 g fresh weight - that's huge considering the fact that "regular" spinach contains < 0.01µg/100g vitamin B12.
  
  In view of the fact that the RDA for B12 is 2.4 μg/day that's still too little to be able to cover your B12 needs from spinach alone. Still, in the future we may be seeing other "high B12" vegetables on the market even non-vegetarian dieters may benefit from.
• Fermented Beans and Vegetables -- The Vitamin B12 content of soybeans is low or undetectable. In the course of the fermentation process soybean products are yet loaded with B12, so that fermented soybeans (Tempe, a traditional Indonesian food that's made of fermented soybeans) can contain up to 8.0 μg B12 per 100g (Nout. 1990)
  
  Comparable increases in B12 content have been observed in vegetables that have been fermented with certain lactic acid or propionic bacteria (up to 10µg/100g; Gupta. 1998).
  
  

  

  "Pesticide pollution: Chinese tea may not be safe to drink," this is what you could read on the website of Greenpeace in 2012, already and obviously this has not changed over the last 2 years | read more

  Tea, of which most people forget that it is fermented (not green tea, though), as well can also contain significant amounts of vitamin B12. For black tea (Batabata-cha), scientists have shown that drinking 50 mL/day, equivalent to a daily dose of 1 ng Vitamin B12, for 6 weeks, compensated the B12 deficiency of B12 deficient rodents (Kittaka-Katsura. 2004). As Watanabe et al. point out, results like these "indicate that Vitamin B12 found in fermented black tea is bioavailable in rats." Unfortunately, the same cannot be said for human beings, where the consumption of 1–2 L of the fermented tea drink, which is equivalent to 20–40 ng of Vitamin B12, is not sufficient to meet the RDA of 2.4 μg/day for adult humans.
• Edible Mushrooms --  Zero or trace levels (approximately 0.09 μg/100 g dry weight) of Vitamin B12 were measured in the dried fruiting bodies of porcini mushrooms (Boletussp.), parasol mushrooms (Macrolepiota procera), oyster mushrooms (Pleurotus ostreatus), and black morels (Morchella conica).
  
  

  

  Figure 2: The micronutrients in nori and dried shiitake mushrooms complement each other perfectly (see bottom line for explanation)

  In contrast, the fruiting bodies of black trumpet (Craterellus cornucopioides) and golden chanterelle (Cantharellus cibarius) contained higher levels of Vitamin B12 (1.09–2.65 μg/100 g dry weight) than the above mentioned mushrooms (Watanabe. 2012).
  
  In addition, high levels of Vitamin B12 were detected in the commercially available dried shiitake mushroom fruiting bodies (Lentinula edodes), which are used in various vegetarian dishes. The Vitamin B12 contents of dried shiitake mushroom fruiting bodies (100 g dry weight) significantly varied and the average Vitamin B12 value is approximately 5.61 μg (Bito. 2014). 

In conjunction with algae and algae supplements the aforementioned vegetarian sources of B12 may in fact be sufficient to cover the daily requirements of 2.4µg of vitamin B12.

Milk has a built-in B12 absorption enhancer (learn more). Now you tell me: Who would ever doubt that nature knows best?

Bottom line: Of all vegetarian B12 sources, nori is the one marine source of vitamin B12, Watanabe et al. highlight in particular. The consumption of only 4g of dried purple laver (Vitamin B12 content: 77.6 μg /100 g dry weight) supplies the RDA of 2.4 μg/day. Moreover, nori can be easily consumed as a wrapping for rice and fillings and retains most of its precious B12 content upon heating (Miyamoto. 2009).

In conjunction with dried shiitake mushroom fruiting bodies that contain 18.9 mg of Vitamin D2 (ergocalciferol) and 2.0 mg of iron, both likewise micronturients vegetarians usually don't get enough of in their diets, the dried purple lavers that are rich sources of n-3 polysaturated fatty acids and can be easily integrated in Italian, French, and other forms of Western cuisine, are thus probably the best non-supplemental source of B12 vegetarians can get | Comment on Facebook!

References:

• Bito, Tomohiro, et al. "Characterization of vitamin B< sub> 12</sub> compounds in the fruiting bodies of shiitake mushroom (< i> Lentinula edodes</i>) and bed logs after fruiting of the mushroom." Mycoscience (2014). 
• Carmel, Ralph. "Diagnosis and management of clinical and subclinical cobalamin deficiencies: Why controversies persist in the age of sensitive metabolic testing." Biochimie 95.5 (2013): 1047-1055.
• Gupta, Uma, E. R. Rati, and R. Joseph. "Nutritional quality of lactic fermented bitter gourd and fenugreek leaves." International journal of food sciences and nutrition 49.2 (1998): 101-108. 
• Katz, Max, Sook K. Lee, and Bernard A. Cooper. "Vitamin B12 malabsorption due to a biologically inert intrinsic factor." New England Journal of Medicine 287.9 (1972): 425-429.
• Kittaka-Katsura, Hiromi, et al. "Characterization of corrinoid compounds from a Japanese black tea (Batabata-cha) fermented by bacteria." Journal of agricultural and food chemistry 52.4 (2004): 909-911.
• Miyamoto, Emi, et al. "Characterization of vitamin B12 compounds from Korean purple laver (Porphyra sp.) products." Journal of agricultural and food chemistry 57.7 (2009): 2793-2796.
• Nout, M. J. R., and F. M. Rombouts. "Recent developments in tempe research." Journal of Applied Bacteriology 69.5 (1990): 609-633.
• Pawlak, Roman, et al. "How prevalent is vitamin B12 deficiency among vegetarians?." Nutrition reviews 71.2 (2013): 110-117.
• Pawlak, R., S. E. Lester, and T. Babatunde. "The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature." European journal of clinical nutrition 68.5 (2014): 541-548. 
• Smith, C. Daniel, et al. "Gastric acid secretion and vitamin B12 absorption after vertical Roux-en-Y gastric bypass for morbid obesity." Annals of surgery 218.1 (1993): 91.
• Solomon, Lawrence R. "Cobalamin-responsive disorders in the ambulatory care setting: unreliability of cobalamin, methylmalonic acid, and homocysteine testing." Blood 105.3 (2005): 978-985.
• Stabler, Sally P., and Robert H. Allen. "Vitamin B12 deficiency as a worldwide problem." Annu. Rev. Nutr. 24 (2004): 299-326.
• USDA National Nutrient Database for Standard Reference, Release 18.Vitamin B12 (mg) Content of Selected Foods Per Common Vitamin B-12 Measure, Sorted by Nutrient Content. 2005; Available at: http://www.nal.usda.gov/fnic/foodcomp/Data/SR18/nutrlist/sr18w418.pdf. Accessed 27 November 2011. 
• Watanabe, Fumio, et al. "Characterization and bioavailability of vitamin B12-compounds from edible algae." Journal of nutritional science and vitaminology 48.5 (2002): 325-331.
• Watanabe, Fumio. "Vitamin B12 sources and bioavailability." Experimental Biology and Medicine 232.10 (2007): 1266-1274.
• Watanabe, Fumio, et al. "Characterization of vitamin B 12 compounds in the wild edible mushrooms black trumpet (Craterellus cornucopioides) and golden chanterelle (Cantharellus cibarius)." Journal of nutritional science and vitaminology 58.6 (2012): 438-441.
• Watanabe, Fumio, et al. "Vitamin B12-Containing Plant Food Sources for Vegetarians." Nutrients 6.5 (2014): 1861-1873.

Want B12, But Hate Meat? Drink Milk! SNAC-Fortified Cyanocobalamin 136% More Bioavailable Than Standard B12 - Still Less Effective Than B12 From Cow's Milk

Figure 1: Milk still rules the
world (of B12 supplements ;-)

Vitamin B12 deficiency is probably more prevalent, than many people would have it. The water-soluble vitamin is most abundant in foods of animal origin and vegetarians (let alone vegans) are as much at risk of having inadequate B12 levels, as people with achlorhydria and, consequently, low intrinsic factor (an enzyme that requires an acidic environment to function and facilitate the utilization of B12 from foodstuff), or more generalized disturbances of the gastrointestinal structure due to aging (food-cobalamin malabsorption becomes increasingly prevalent after the age of 50), gastric resection, ileal resection, Crohn's disease, and bacterial overgrowth of the intestine. With vitamin B12 deficiency affecting cell division and precipitating to megaloblastic anaemia and neuropathy, close monitoring not only of vitamin B12 intake, but also of its proper utilization is of utmost importance for people belonging to one of the aforementioned groups.

Scientists from Emisphere Technologies in Cedar Knolls, New Jersey, have now come up with a new cyanocobalamin/SNAC coformulation, in which the sodium caprylic acid salt, N-[8-(2-hydroxybenzoyl)amino]caprylate (SNAC), a proven drug delivery agent, shall facilitate a more pronounced and more reliable absorption of orally supplemented vitamin B12 (Castelli. 2011). The formula, which contained 5-mg cyanocobalamin and 100-mg SNAC was administered to 6 human subjects in the fasted state in the form of 1 tablet, which had to be taken with 50 mL of water. Blood samples were taken at staggered intervals with the last blood draw taking place 24h after the ingestion of the B12/SNAC coformulation.

Figure 1: Time to and maximal serum concentration of B12 after oral administration or infusion of cyanocobalamine with and without SNAC; note: in order to compensate for the major differences between oral cyonocobalamine with and without SNAC a logarithmic scale was used (data adapted from Castelli. 2011).

As expected the concomitant administration of sodium N-[8-(2-hydroxybenzoyl)amino]caprylate (SNAC) increased the meager biovalability of cyanocobalamine (which is absorbed really poorly, anyway) significantly:

Absolute bioavailability of B12 with the SNAC formulation was calculated from non–baseline-adjusted data to be 5.09% and was significantly greater (P < 0.05) than the commercial formulation (2.16%).

In view of the recently elucidated bioavailability of natural B12 from plain cow's milk (Matte. 2011), or should I say "liquid white gold", the 136% increase in bioavailability Christina Castelli and her coworkers achieved with their artificial combination of B12+SNAC appear quite ludicrous. 8%-10% that is the bioavailability et al. report in Jacques Matte and his colleagues from Canada report in their study on the bioavailability of vitamin B12 from cow's milk. Granted, this is a pig model, but other than rodents, which are usually used when it comes to studies, in which surgical interventions are necessary to elucidate the exact pharmacodynamics of a specific drug, pigs provide a very adequate model for the human gastrointestinal system, or as Miller and Ullrey already stated it in a 1987 paper on the "The Pig as an Animal Model For Human Nutrition" (Miller. 1987)

[...]with the possible exception of nonhuman primates, it is apparent that the omnivorous pig is one of the best models for study of nutrition issues in the omnivorous human.

This long established adequacy of the pig model of the human gastrointestinal tract has only recently been confirmed by Goulloteau et al. (Guilloteau. 2010). Matte et al.'s result that vitamin B12, which is naturally and abundantly present in cows’ milk, is more available at the intestinal level than the synthetic form - even if the latter is supplemented with SNAC - are thus very likely to apply to humans, as well.

Figure 2: Pharmacokinetics of vitamin B12 from different sources measured in pigs with an ultrasonic flow probe around the portal vein and a catheter inside the portal vein; values expressed as differences vs. unsupplemented animals; both values for cyanocobalamine alone are effectively 0, i.e not different from unsupplemented pigs (data adapted from Matte. 2011).

These results are also in accordance with retrospective studies in human subjects showing that vitamin B12 status is highly correlated with dairy product intake and studies on the absorption (absorption = entering the cells vs. bioavailability = becoming available in the blood stream) of vitamin B12 from dairy products in older men and women (>60y) by Robert M. Russel et al. (Russel. 2001), who report absorption of up to 65% for milk, which would be almost identical to the generally accepted absorption coefficient for meat products.

Note: Using a pig model Matte et al. were able to actually measure the portal-drained viscera (PDV) flux of vitamin B12, which provides more reliable results than radio-labelling studies, as they were used in Russel et al. It is thus all the more intriguing that the PDV for the unsupplemented diet or cyanocobalamin supplements [...] were not different from 0", or in other words - providing pigs with cyanocobalamine, which is the form of vitamin B12 that is used in most common dietary supplements, had no effect  on serum B12 concentrations, at all.

So, what does this tell you, after all? Well, let me phase it like that: If you have a Ferrari Enzo (milk and meat) waiting for you at the front door (in the fridge), wouldn't it be plain-out stupid to try to chip-tune (add SNAC) the family car (cyanocobalamine)? An the moral of the Story? Eat, don't supplement your vitamins!

1000mcg Oral Vitamin B12 do not Bring Low Plasma Levels Back to Normal

You probably take a multivitamin, do you? Well, you eat healthy, as well? But does this mean you get enough of all nutrients? Maybe... maybe not. In a recent study (Baer. 2011) on vitamin B12 deficiency and supplementation in healthy young women, of the 300 participants, 137, i.e. 46%, had low-normal plasma levels of vitamin B12.

Interestingly, in participants with very low B12 levels, neither supplementation with 1000mcg of oral methylcobalamin, nor the consumption of a cereal meal (probably a bad idea, anyway) 4x/week for three months was able to restore B12 to an acceptable level:

Supplementation of either vitamin B12 pill or 100% RDA fortified cereal for 3 consecutive months resulted in significant (p < 0.05) increase in mean plasma vitamin B12 levels in all subjects (Table 4). Subjects whose baseline plasma vitamin B12 status was < 200 pg/ml were not observed to increase plasma vitamin B12 levels to at or above the 250 pg/ml benchmark following three months supplementation by either pills or 100% fortified cereal.

The scientists also have an answer as to why this might have been the case - malabsorption:

Upwards of 40% of all subjects who demonstrated plasma vitamin B12 values at or below the low-normal range reported daily use of medications associated with adversely affecting vitamin B12 absorption—significantly higher than the number of subjects who were observed to have plasma vitamin B12 levels above 250 pg/ml.

Bear & Parker's advice to people, especially from this "high-risk" group, is thus to supplement with "a higher dose of supplemental vitamin B12 (oral pill form) or sublingual methylcobalamin or IM methylcobalamin" in order to sufficiently correct vitamin B12 status.