Pure, Isolated USP-Type Nutrients Vs “Whole-Food-Grown-Type” Nutrients
Questions About Absorption
By Michael Mooney, April, 2008
(Also read my 9600 word article about this.)

I have heard that "whole-food-grown-type" multivitamins absorb much better than the isolated USP-type vitamins and minerals that are found in most multivitamins. Companies that sell them say they are actually food and this makes them more natural to the body. Can you tell me which type of nutrients absorbs the best?

You may be surprised to find out that although quality natural whole food is the basis for all health, isolated USP-type nutrients generally absorb better than individual nutrients contained in foods. This is one reason complete daily vitamin supplements can be an important addition to your diet if your diet is not perfect. (A "perfect" diet would include at least ten to fifteen servings of raw fruits and vegetables per day, according to a landmark study that looked at foraging diets that was published in the New England Journal of Medicine in 1985.44) Additionally, so-called "whole-food-grown-type" multivitamins are not really food in a literal sense. They are USP-type vitamins mixed with tablet amounts of food materials in a laboratory process. These nutrients are then marketed as “food.” However, the tablet amount of food they contain gives you too little food and too little nutrients to be of consequence for supplemental needs. Although some supplement companies make claims of tremendously improved activity and absorption, none of these products have been proven by independent scientific analysis to absorb any better than other supplemental nutrients or the USP-type vitamins and minerals they are made from. The claims are simply manufacturers' marketing statements.

What Are USP-Type Nutrients?

USP means United States Pharmacopia, which is an established standard that confirms that the nutrient is a pure, safe, perfectly formed replica of the same molecule found in natural whole foods or, as in the case of folic acid, a pure, safe synthesized version of a nutrient.

Do USP-Type Nutrients Absorb Better Or Worse Than Nutrients In Foods?

Most USP-type nutrients absorb better than nutrients in foods. This is due to the fact that USP-type nutrients are free and not bound to anything, whereas the nutrients in foods are bound to various elements, including proteins, which have to be broken down through digestion before the nutrient can be freed to be absorbed by the body. The process of digestion can significantly affect the amount of the nutrient that is gleaned from food. Published studies confirm that nutrients are only absorbed in their free, isolated state at the intestinal wall. Unbound, isolated USP-type nutrients are ready to enter the intestinal wall in a pure, free state and, therefore, are absorbed in a more efficient and predictable manner. While there are notions that foods contain carrier proteins, sometimes mistakenly called "protein chaperones" that can enhance nutrient absorption, the carrier proteins that bring nutrients into the body are created exclusively in intestinal cells and attached to the free-state nutrients by the body. These carrier proteins are not derived from outside sources, such as vitamin supplements or foods.

Dr. Gunther Blobel, who won the 1999 Nobel Prize for his work on protein chaperones detailed how these proteins are created in the body to distribute nutrients within the body. They are not derived from outside sources. When asked, Dr. Blobel dismissed claims that "whole-food-grown-type" supplements benefit from having protein chaperones as "utter nonsense and misleading." (See page 13 in the linked document.)

Are All Multi-Vitamins Made With USP-Type Nutrients?

All vitamins and minerals sold in the United States, including “whole-food-grown-type” vitamins, are made with USP-type nutrients. Some vendors of nutrients mix USP-type nutrients with food materials in laboratory processes that are claimed by supplement companies to enhance absorption and effectiveness in the body. These processes include such strategies as mixing the nutrients into foods that are fermented with yeast (Saccharomyces cerevisiae) or probiotics, such as acidophilus. These proprietary products are marketed as “food-grown-type” nutrients, “food-state-type” nutrients," "food-matrix-type" nutrients, “homeostatic-food-type” nutrients, “100% whole-food-grown-type” nutrients, “probiotic-type” nutrients and various other trade names. Claims are made that the laboratory fermentation process bonds the nutrient into the food which makes the tableted supplement into a “food.” This may make it sound like the product is more natural and thus more absorbable and more effective than pure, isolated USP-type nutrients. However, as the table below illustrates, if the USP-nutrients are actually bonded into the food - which is questionable, this might make them less absorbable, not more.

Nutrient Absorption Comparison Table
USP-Type Nutrients And Nutrients In Food

This table shows the results of twenty-three independent scientific studies evaluating the absorption rates of USP-type nutrients and the same nutrient as found in foods. Some studies do not provide exact percentages of absorption, but rather tell whether absorption was equal or greater. Some are not direct comparisons, but comparisons of different study results. There are often wide variations between studies, but the general patterns are unmistakable. Isolated USP-type vitamins and minerals absorb about as well as, or better than most vitamins and minerals in foods.

Note 1: The % symbol refers to the percentage absorption of the referenced item. AUC means "area under the curve," measuring the total amount in a blood test over a specific period of time.
Note 2: The percentage difference can be looked at two different ways. For instance, USP-Type Vitamin K could be said to absorb 22.76 percent better or 575 percent better, as it is actually 5.75 times better absorbed. If the second method is used to calculate percentages, each of the other nutrients would show a similar greater percentage absorption.


% Absorption


% Absorption


% Absorption


% Absorption


% Absorption

Best Source

Percent Difference


Calcium Carbonate
Calcium Citrate

39% 1
39% 2


5.1% 3


32.1% 1

Sardine Bones

23% 4


40.9% 5

Kale Calcium

1.9%  Better


Calcium Carbonate

6, 7






All Forms



Folic Acid




Orange Juice






USP-Grade Folic Acid

8% to 65% Better


Folic Acid





USP-Grade Folic Acid

60% Better


Vitamin C
(Ascorbic Acid)

13, 14



Orange Juice


Cooked Broccoli


Raw Broccoli

20% less

All Forms
(Except Raw Broccoli Is 20% Less)

(Except Raw Broccoli Is 20% Less)


Vitamin B6

65% 15

Orange Juice



Vitamin B6

35% Better


Beta Carotene

93% 16


82.9% to 88.8%


USP-Grade Beta Carotene

4% to 10% Better



66% 17

Wholewheat Bread

17% 18


20% 19


USP-Grade Zinc

46% to 49% Better


Vitamin K (Phylloquinone)

(AUC) 43

Fresh Spinach

4.79 (AUC)


USP-Grade Vitamin K 

22.76 or 575% Better (See Note 2) 


Vitamin B12

Equal 44, 45, 46






Some Food Materials That Can Inhibit Nutrient Absorption: Yeast (Saccharomyces Cerevisiae)

One food material that some manufacturers include in the products that exhibits decreased absorption of an important nutrient it contains is yeast. Folic acid is a nutrient that is critically needed by pregnant mothers because it is proven to reduce birth defects with the reduction of birth defects being greater at higher doses. Early studies (1947, 1952) showed that the folic acid contained in a food-type yeast (Sacchromyces cerevisiae) exhibited very poor absorption compared to pure USP-type folic acid. (8,9,20,21,22,23) Further studies determined that the digestion of folic acid in yeast is compromised in the stomach by a protein that binds folic acid into the yeast called gamma glutamyl peptide. Gamma glutamyl peptide is not digestable in human stomachs. (21,22,25)

One study stated, “Yeast folic acid is [absorbed] only one-third as well as [USP-type folic acid].” (22) Because “gastric juice and duodenal fluid are inactive against the gamma glutamyl peptide chain of yeast folic acid digestion of yeast folic acid cannot occur in the stomach, but must take place in the jejunum in the intestine.” (20,24,25) Yeast is known as a poor source of absorbable folic acid and is stated to be “poorly representative of natural dietary folic acid.” (23) Therefore, yeast-derived folic acid would be a poor source of folic acid for pregnant mothers. However, another study stated that folic acid in other foods, in general, “…is not as available as [USP-type folic acid].” (25) Food sources of folic acid are generally about 40 percent less digestable and absorbable than pure, isolated USP-type folic acid. (9,10,11,12)

Other Foods That Contain Absorption Inhibitors

A binding protein in milk compromises the absorption of folic acid in milk. (26) Foods can also have naturally occurring inhibitors that reduce the effect of the enzyme that frees folic acid from the food-protein. Some beans, like soybeans, red kidney beans, and lima beans contain potent folic acid absorption inhibitors, so folic acid in these beans is generally very poorly absorbed. (27)

Many foods contain elements other than proteins that strongly inhibit absorption of a specific vitamin. For instance, Vitamin B1 (thiamine) absorption is compromised in raw fish (sushi), blueberries, black currents, red chicory, brussel sprouts, red cabbage, red beets, coffee and some teas. (28,29) These foods contain potent anti-thiamine factors, like caffeic acid, salicylic acid (similar to aspirin) and tannic acid, which inhibit the absorption of Vitamin B1 (thiamine).

Probiotics And Nutrient Absorption: Yogurt

Some “whole-food-grown-type” vitamins are processed with probiotics in an effort to increase absorption. Does this work? Probiotic-rich foods, such as yogurt, kefir or the probiotic bacteria they contain are sometimes assumed to cause an improvement in nutrient digestion because probiotics, like lactobacillus, effectively break down things like lactose, a carbohydrate in milk. However, no data was located which indicated that fermentation with probiotics has a significant effect on improving the absorption of vitamins and minerals. In fact, published studies show no difference in the absorption of important nutrients like calcium from foods made with probiotics, such as yogurt. As shown below, calcium carbonate and milk calcium absorb equally to calcium in yogurt. (6,7)

Probiotics Cause Decreases In The Amounts Of Most Nutrients

Additionally, several studies confirmed that the fermentation that turns milk into yogurt “caused a decrease in the amounts of most vitamins ranging from 2 percent for niacin to 60 percent for biotin.” (30,31,32,33) Vitamin C also decreased, while other studies showed decreases in Vitamin B5, (34) Vitamin B12 (35) and manganese and magnesium, (36) with only folic acid increasing because folic acid can be synthesized during the fermentation process. (31,37) This is because probiotic organisms, like any life form, consume various nutrients to survive. Probiotics consume nutrients that your body might use to keep themselves alive and functioning during the fermentation process. Fermentation with probiotics does not improve the absorption of nutrients such as calcium, while it can actually decrease the amounts of many of the vitamins and other nutrients in the foods that are fermented.

All Independently Published Studies Through-Out History Use USP-Type Nutrients

All of the over 200,000 published studies during the last sixty years that show the effectiveness and safety of vitamins and minerals used isolated USP-type nutrients supplemented at appropriate doses. Examples include:

1. Pregnant women who added 1,200 mg or more of USP-type calcium carbonate to their diet had newborn babies with about 15 percent greater total body bone mineral content that creates bones than mothers who took less calcium. (38)

2. Senior women who were losing bone gained an average of 3.7 percent in their spine and 3 percent in their hips when they took 1,000 mg of USP-type calcium carbonate per day over a two year period of time. When the only calcium they consumed came from their diet (683 mg average per day) they lost 3 percent of their greater bone mineral density. (39)

3. Senior women who took between 1,000 mg and 5,000 mg of USP-type Vitamin C had five percent greater bone density over a three year period of time than senior women who took 500 mg or less. (40)

4. In a study of 630 women, when women took 200 mg of USP-type Vitamin B6 (pyridoxine) per day, 79 percent of the women experienced significant reductions in PMS, while no significant reduction in PMS was seen with women who took 40 mg of B6. (41)

5. Pregnant women who took 400 mcg of USP-type folic acid had babies with 40 percent less birth defects than women who only got folic acid from their food. (42)

Note: There are no independently published studies in peer-reviewed journals showing similar results with “whole-food-grown-type” nutrients. In fact, there are no independently published studies that look at “whole-food-grown-type” nutrients in peer-reviewed medical journals. The seven studies that were located were sponsored by manufacturers of these products and conducted by one paid researcher. These studies did not show significant advantages related to absorption for “whole-food-grown-type” nutrients. To review these studies, ask manufacturers of these products for copies of these studies.

USP Nutrients: Less Tablets And Less Cost

Because of the space taken up by food materials, “whole-food-grown-type” nutrients require 4 to 12 times more tablets than USP-type nutrients to deliver the same potencies. Because of the added cost of synthesis and manufacture in laboratories, “whole-food-grown-type” nutrients cost 4 to 14 times more than the USP-type nutrients they are made from. Considering the consistent absorption of USP-type nutrients, and the fact that they require less tablets while costing less, USP-type nutrients remain the standard for use in dietary supplements. USP-type vitamins and a healthy diet can work together to give you the best potential for your optimal long-term health.


  1. Sheikh MS, et al. Gastrointestinal absorption of calcium from milk and calcium salts. NEJM (1987) Aug 27, 317(9): 532-536.
  2. Harvey JA, et al. Superior calcium absorption from calcium citrate than calcium carbonate using external forearm counting. J Am Coll Nutri (1990) Dec;9(6):583-587.
  3. Heaney RP, et al. Calcium absorbability from spinach. Am J Clin Nutri Nutrition 47(4):707-9 1988 Apr. 
  4. Hansen M, et al. Calcium absorption from small soft-boned fish. Journal of Trace Elements and Medical Biology, 12(3):148-54 1998 Nov.
  5. Heaney RP, et al. Calcium absorption from kale. Am J Clin Nutri Nutrition 51(4):656-7 1990 Apr
  6. Recker RR et al. Calcium absorbability from milk products, an imitation milk, and calcium carbonate. Am J Clin Nutri 1988 Jan;47(1):93-5.
  7. Smith TM, Kolars JC, Savaiano DA, Levitt MD. Absorption of calcium from milk and yogurt. Am J Clin Nutri 1985 Dec;42(6):1197-200.
  8. Spray GH, Witts LJ. The utilization of folic acid from natural sources. Clin Sci 1952, 11:273-81.
  9. Perry J, Chanarin I. Absorption and utilization of polyglutamyl forms of folate in man. Brit Med J, 1968, iv:456-549.
  10. Tamura T, Stokstad EL. The availability of food folate in man. Brit J Haem (England), Oct 1973, 25(4):513-32.
  11. The availability of food folate in man. Nutri Rev June, 1974, 32(6): 167-170.
  12. Neuhouser MA, et al. Absorption of dietary and supplemental folate in women with prior pregnancies with neural tube defects and controls. J Am Coll Nutri, 17(6):625-3
  13. Pelletier O, Keith MO. Bioavailability of synthetic and natural ascorbic acid. J Am Diet Assoc 64; March 1974, 271-5.
  14. Mangels AR, et al. The bioavailability to humans of ascorbic acid from oranges, orange juice and cooked broccoli is similar to that of synthetic ascorbic acid. J Nutri, 123:1054-61, 1993.0.
  15. Nelson EW, et al. Comparative human intestinal bioavailability of Vitamin B6 from a synthetic and a natural source. J Nutri 106:1433-1437, 1976
  16. Annapurna VV, et al. Spirulina as a source of vitamin A. Plant Foods Hum Nutri 1991 Apr;41(2):125-34.
  17. Lomback I, et al. Absorption of zinc in acrodermatitis enteropathica. Lancet 1975;I:855.
  18. Sandstrom B, et al. Zinc absorption from composite meals. Significance of wheat extraction rate, zinc, calcium and protein content in meals based on bread. Am J Clin Nur 1980;33:739-45.
  19. Sandstrom B. et al. Zinc absorption from composite meals. II. Influence of the main protein source. Am J Clin Nutri 1980;33:1778-83.
  20. Buyze HG, Engel C. The activity of digestion enzymes on pteroylglutamic acid (folic acid) and pteroyl-hexa-glutamyl-glutamic acid (folic acid conjugate). Biochemica et Biophysica Acta, 2, 217-222. 1948 
  21. Rosenberg I H. Absorption and malabsorption of folates. Clin Haem, October, 1976, 5(3):589-618.
  22. Swenseid ME, et al. Metabolic function of pteroylglutamic acid and its hexaglutamyl conjugate. II. Urinary excretion studies on normal persons. Effect of a conjugase inhibitor. J Lab Clin Med 32:23-27, 1947.
  23. Spray GH. The ultilization of folic acid from natural sources. Clin Sci 1952, 11:425-8.
  24. Baugh CM, et al. Studies on the absorption and metabolism of folic acid. Folate absorption in the dog after exposure of isolated intestinal segments to synthetic pteroylpolyglutamates of various chain lengths. J Clin Invest 1971 Oct;50(10):2009-21.
  25. Bernstein LH, et al. Gamma glutamyl carboxypeptidase (conjugase), the folic acid-releasing enzyme of intestinal mucosa. Am J Clin Nutr 1970 Jul;23(7):919-25.
  26. Ghitis, J. The folate binding in milk. Am J Clin Nutri 1967 Jan;20(1):1-4.
  27. Krumdieck CL, et al. A naturally occurring inhibitor of folic caid conjugase (pteroyl-polyglutamyl hydrolase) in beans and other pulses. Am J Clin Nutri 1973, 26:460-61.
  28. Hilker DM, et al. Anti-thiamines of plant origin: Their chemical nature and mode of action. Ann NY Acad Sci 1982; 378:137-45.
  29. Bender D. Nutritional Biochemistry of Vitamins. New York: Cambridge University Press, 1992, pp 126-155.
  30. Hewitt D, Bancroft HJ. Nutritional value of yogurt. J Dair Res (1985), 52:197-207.
  31. Reddy KP, et al. B-complex vitamins in cultured and acidified yogurt. J Dair Sci (1976) 59:191-195
  32. Bhagvat K, Sekhon NS. Nutritional requirements of Lactobacillus bulgaricus, L. Acidophilus and Streptococcus lactis. Current Science 1944, 13:45.
  33. Pray EG. Growth factors of Streptococcus thermophilus. J Bacteriol 1941, 42:291.
  34. Snell E, et al. Pantothenic acid and nicotinic acid as growth factors for lactic acid bacteria. J Am Chem Soc 1938, 60:2825.
  35. Rasic J, Panic B. Changes in vitamin B12 content in the preparation of yogurt. Arch. Poljopr. Nauk. 1961, 14:94 (cited Dairy Science Abstract 1961, 23:561.
  36. Sabine D, et al. Trace element requirements of lactobacillus acidophilus. Nature 214; April 29, 1967:52036.
  37. Alm L. Effect of fermentation on B-vitamin content of milk in Sweden. J Dair Sci (1982) 65:353-359.
  38. Koo WW, et al. Maternal calcium supplementation and fetal bone mineralization. Obstet Gynecol 1999 Oct;94(4):577-582.
  39. Storm D, et al. Calcium supplementation prevents seasonal bone loss and changes in biochemical markers of bone turnover in elderly New England women: a randomized placebo-controlled trial. Clin Endocrinol Metab, 83(11):3817-25 1998 Nov.
  40. Morton DJ, et al. Vitamin C supplement use and bone mineral density in postmenopausal women. J Bone Min Res 2001;16(1):135-140.
  41. Brush MG, et al. Pyridoxine in the treatment of premenstrual syndrome: a retrospective survey in 630 patients. Brit J Clin Pract 1988;l42(11):448-4562.
  42. Garcia-Morales MA, and associates. Peri-conceptual use of folic acid in the prevention of neural tube defects: current concepts. Ginecology and Obstetrics of Mexico 1996 Sep;64:418-21.
  43. Garber AK and associates. Comparison of phylloquinone bioavailability from food sources or a supplement in human subjects. J Nutr. 1999 Jun;129(6):1201-3.
  44. 3. Okuda, K and associates. Absorption of liver-bound vitamin B12 in relation to intrinsic factor. Blood 1968, 32:313-323.
  45. Sullivan, L and associates. Evidence against preferential intestinal absorption of physiologic quantities of liver-bound vitamin B12 by patients with pernicious anemia. American Journal of Clinical Nutrition 1962, 11:568-573.
  46. Heyssel, RM, and associates. Vitamin B12 turnover in man. The assimilation of vitamin B12 from natural foodstuff by man and estimates of minimal daily dietary requirements. American Journal of Clinical Nutrition 1966, 18:176-184.

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