J. Vinson H. Al Kharrat, and L. Andreoli Department of Chemistry, University of Scranton, Scranton, PA
Aloe Vera Gel Increases Absorption of both Vitamins C and E
by Scott Siegel
search of the medical literature revealed that there are no articles
describing the effect of Aloe vera liquid preparations' consumption on
the absorption of either water-soluble or fat-soluble vitamins. Millions
of Americans, and untold millions of other populations consume
vitamins, it is also well known that foods, beverages, drugs, or aging
may adversely affect absorption. A very large number of people around
the world also consume Aloe. It is thus vitally important that the
combination of Aloe and vitamins be tested. Our research group took up
For water-soluble vitamin C data was obtained on 8
normal subjects. Two forms of Aloe (AVL, a whole leaf extract, or AVG, a
gel) liquid were tested in this study. The subjects appeared at a local
clinical lab after an overnight fast consumed in a random fashion 500
mg of a vitamin C tablet with either 60 mL (2 oz) of either water
(control), AVG, or AVL. The liquid was sipped over 5 minutes. Blood
sampling was at 1, 2, 4, 6, 8, and 24 hours (fasting) post-dosing
Subjects were allowed to eat their normal lunch and evening meals. One
week and two weeks later the other liquids were consumed and the
sampling repeated. Blood was converted to plasma, mixed with
metaphosphoric acid preservative, and stored at -80°C until assay by
HPLC. Changes in plasma ascorbate after consumption of the different
liquids are shown in Figure 1. The areas under the average plasma
ascorbate change with time curves correspond to the bioavailabiity. The
areas were determined by a graphics program. The relative areas were as
follows: vitamin C alone 100%, AVG 304 % and AVL 80 %. Thus vitamin C
was 3 times more bioavailable when taken with AVG but was 20% / less
bioavailable with AVL. The Aloe preparations caused the absorption of
ascorbate to be slowed as evidenced by the time for maximal absorption
which was 2 hours for vitamin C alone, 8 hours for both AVL and AVG. A
slow release drug, for instance, usually has greater efficacy for a
longer period of time. AVG also increased absorption and caused a larger
ascorbate concentration at 8 hours and 24 hours, thus providing more
benefit. A review of the literature shows that Aloe is only the second
matrix that improves ascorbic acid absorption, the first being a citrus
extract (1). Since vitamin C is the most common water- soluble vitamin
supplement, this Aloe result has wide-ranging applications.
E is a fat-soluble vitamin that was given to 10 normal subjects. The
same procedure as with vitamin C was followed except that vitamin E
(tocopherol acetate) was given in the form of a soft capsule at a dose
of 400 mg. The change in plasma E was calculated and illustrated in
Figure 2. The vitamin E alone was poorly absorbed, as expected under
fasting conditions, and in some time periods with the control the
subjects had less E than at baseline, obviously an unhealthy situation.
With the Aloe preparations after consumption, the subjects had higher
plasma E than at baseline at all times even at 24 hours. Compared to the
baseline, both Aloes in Figure 2 had much higher changes in plasma E at
8 and 24 hours. Thus the Aloes kept an elevated plasma E longer than
the control without Aloes. The relative areas of the curves in Figure 3
were as follows: vitamin E alone using only the above baseline data
100%, AVL 198% and AVG 369%. Thus vitamin E was 2 times more
bioavailable with AVL and over 3 times more with AVG. The E absorption
was slowed with the Aloe liquids. The vitamin E taken alone produced a
plasma E maximum at 4 hours, which then declined. The maximum occurred
at 6 hours for AVL and 8 hours for AVG. Aloe preparations taken with E
greatly improved the absorption of vitamin E and maintained plasma E
concentrations for longer periods of time compared to the vitamin E
alone. Aloe is unique in its ability to improve the bioavailabiity of
both vitamin C and E.
The elderly population is greatly
increasing in developed nations. This group is especially vulnerable to
vitamin deficiency due to age-related decreases in absorption, reduced
food intake, and increased drug use (2). Hemodialysis patients have low
levels of ascorbate that is further reduced with hemodialysis (3). It is
well known that fats improve the absorption of the lipid- soluble
vitamin E but, many people take vitamins on an empty stomach and dieters
consume it with a low-fat meal. In addition Orlistat, a fat absorption
inhibitor used for weight loss (4), and Olestra, a fat substitute (5)
significantly decreases plasma vitamin E when consumed for a long period
of time. The results of our study indicate that Aloe preparations can
greatly improve the absorption of both a water- and fat-soluble vitamin,
is of great significance, and a potential benefit to the population at
large. Since Aloe vera and vitamins C and E are commonly used in health
cosmetics, the combination should be investigated to determine if Aloe
improves skin absorption of these vitamins.
A review of
recent literature indicates that an ingredient of Aloe has potent
immunostimulatory activity (6) that has implications for wound healing
and immunotherapy, perhaps providing greatest efficacy in combination
with drugs where synergism could take place. An Aloe leaf pulp extract
showed hypoglycemic activity with type I (Insulin-Dependent Diabetes
Mellitus) and type II (non Insulin-Dependent Diabetes Meffitus) diabetic
rats (7). In two rat models of arthritis Aloe significantly reduced paw
swelling (8). Thus scientific research should continue with Aloe since
many promising health benefits may result.
1. Vinson, J, Bose, P. Comparative bioavailabiity to humans of ascorbic acid alone or in a citrus extract.
Am. J. Cli Nutr 1988; 48: 601-4.
2. Van den Berg, H, and der Gaag M., Hendriks, H. Influence of lifestyle on vitamin bioavailabiity.
Mt. J. Vitamin Res. 2002; 72: 53-59.
3. Wang, S., Elde T., Sogn, E., Berg, J, Sund J. Plasma ascorbic acid in patients undergoing chronic
hemodialysis. Eur. J. Pharmacol 1999; 55: 527-532.
4. Melia, A., Koss-Twardy, S., Zhi, J. The effect of orlistat, an inhibitor of dietary fat absorption, absorption
of vitamins A and E in healthy volunteers. J. Clin. Pharmacol. 1996; 36: 647-653.
5. Kelly S., Shorthouse, M., Cotterell, J., Riordan, A., Lee, A., Thurnham, D., Hanka, R., Hunter, 3.
A 3-month, double-blind, controlled trial of feeding with sucrose polyester in human volunteers. Br J Nutr 1998; 80:41-49.
6. Pugh, N., Ross, S., ElSohly, M., Pasco, S. Characterization of Aloeride, a new high-molecular-weight
polysaccharide from Aloe vera with potent immunostimulatory activity. 3. Agric. Food Chem. 2001; 49:1030-1034.
7. Okyar, A., Can, A., Akev, N., Baktir, G., Sutlupinar, N. Effect of Aloe vera leaves on blood
glucose level in type I and type H diabetic rat models. Phytother. Res. 2001; 15:157-161.
8. Davis, R., Leitner, M., Russo, J., Byrne, M. Anti-inflammatory activity of Aloe vera against a spectrum
of irritants. 3. Am. Podiatr. Med. Assoc. 1989; 79: 263-276.
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