Found in almost any multivitamin, immune support, ergogenic aid or fortified orange juice, vitamin C is taken for a variety of reasons necessary for our health. But have you wondered why?
Benefits of vitamin C
Vitamin C (ascorbic acid) plays an important role in various functions of our body such as (1):
- Maintaining the normal function of the immune system
- Helping with collagen formation for the normal function of blood vessels, bones, cartilage, gums, skin and teeth
- Ensuring the normal functioning of the nervous system
- Reducing tiredness and fatigue and
- Helping to protect cells from oxidative stress
Limitations of vitamin C
As listed above, there are many reasons for taking vitamin C supplements. The most important reason is that the human body is unable to produce this water-soluble vitamin by itself (2). It is essential, therefore, that we consume adequate doses of this essential, water-soluble vitamin through our diet or food supplements.
The EFSA recommends 95-110 mg/day of vitamin C for all healthy adults (3). No upper limit has been set within the EU although in the USA, the limit has been set at 2 000 mg/day (2).
In the market, doses of vitamin C higher than 500 mg/day are sold as high-dose supplements. The argument for high-dose vitamin C is that the DRV recommendation is for healthy people; however when the body is under stress or when one is ill, higher dosages are required to counter these “attacks” (4,5). Unfortunately, there are also two well-known problems with consuming high-dose ascorbic acid supplements.
- Taking high dosages of vitamin C orally doesn’t necessarily mean more of it is absorbed. There is a limit to how much the body can absorb. In fact, scientific studies have shown that at single doses above 1 000 mg/day, absorption falls to less than 50% (2)! This makes high dosages inefficient.
- The more you take, the more likely you will get unpleasant GI side effects such as nausea and diarrhoea.
Luckily, encapsulation of the vitamin into liposomes could help with both of these problems.
Liposomes are the solution
The GI distress caused by too much vitamin C is due to osmotic forces. This basically means vitamin C attracts water, leading to dehydration. In turn, this can cause diarrhoea, nausea, abdominal cramps and other gastrointestinal disturbances (2).
By encapsulating vitamin C in liposomes, the exposure to the GI tract is reduced. This reduces its dehydrating side effects (5).
Additionally, the absorption of vitamin C in the intestine is carried out through a number of cellular transporters. However, these transporters are easily saturated leading to a limited absorption of vitamin C from supplements (5). Packing vitamin C into liposomes could help it passively cross the intestinal cells and avoid these intestinal transport barriers. Further, due to the re-direction of the liposomes into the lymphatic drainage, the encapsulated vitamin C is directly deposited into the bloodstream. Since the cells of the rest of the body have a different set of transporters for vitamin C, more vitamin C is directly absorbed from the blood (5).
Why did we want to study our formulation?
Our mission is to show that liposomal encapsulated supplements can really make a difference to supplement absorption. With this human study, we wanted to prove that our product can easily overcome the problem associated with high-dose vitamin C absorption.
The bioavailability study described here was performed in association with our study partner, Surya Research Clinics, India.
What did we look at
- We tested 40 healthy volunteers (20-50 years) divided randomly into four groups. This is an adequately sized group for pilot tests like ours.
- 10 people were given 1 000mg of our liquid liposomal vitamin C (liposomal product A (LLA) group). Another 10 other people received a competitor’s liquid liposomal formulation (LLB group). The third group was provided 1 000mg of powdered liposomal vitamin C in capsule form (PL group) and the fourth group of 10 people received 1 000mg of powdered non-liposomal vitamin C in tablet form (NL group)
- Next, blood was drawn before giving the participants the supplements (a baseline measurement). Blood was also drawn every two hours for the first 12 hours after supplementation and every four hours for the next 12 hours .i.e. the study was performed over a 24 hour period. The plasma ascorbic acid levels were then determined in the laboratory of the study centre. We did this for all the study groups in order to measure how much and how fast the supplement was absorbed. That way, we could compare their effectiveness.
- Once we received the laboratory plasma ascorbic acid level results for every participant, at every time point, we calculated the average maximum blood concentration (Cmax) of vitamin C per group. The time at which it occurred (Tmax) was also calculated.
- The area under the curve (AUC) was calculated as well. This is the pharmacological equivalent of the bioavailability. It tells us how much of an ingested nutrient reaches the bloodstream, for how long it stays there, and thus how much of it can actively be used by the body.
1. Maximum Blood Concentration
The average maximum ascorbic acid concentration (Cmax) in the group that received our liposomal formulation was 2.78 mg/dL. The Cmax for the LLB group was similar at 2.51 mg/dL. As expected, the Cmax of the non-liposomal group was lower at 1.12 mg/dL. Surprisingly, the powdered liposomal group only achieved a Cmax of 0.97 mg/dL!
The above findings suggest that liquid liposomal formulations are able to help vitamin C to overcome the gastrointestinal barriers. A higher amount of vitamin C is thus, able to enter the bloodstream.
2. Time until Maximum Blood Concentration
As can be seen in the image below, although an increase in plasma ascorbic acid levels were detected in all groups even at 2 hours after supplementation, the concentration gradually increased in the group that received our liposomal formulation over 12 hours. The plasma ascorbic acid levels in all other groups reduced much before this time.
Since the uptake mechanisms of the liquid liposomal groups (LLA and LLB) are different from that of the powdered groups (PL and NL), the time taken for the vitamin C to reach the bloodstream are also different. This also suggests that the release of vitamin C into the bloodstream is sustained and slow thanks to liposomal encapsulation. It is probable therefore, that the supplement’s effect could last longer. This could reduce the need for multiple dosing.
3. How did the Groups Compare?
We looked further at the data to see if there were differences between the groups for all other parameters. We plotted this as a graph pictured in the image below.
- First we looked at the baseline plasma ascorbic acid measurements i.e. before the supplement was taken. These values were almost the same and not statistically different. This is good because it means that each group started on a level playing field.
2. Next we looked at the time after supplementation. As explained above and in table 1, it took only 4 hours for PL and NL to reach their Tmax. However, it took 8 hours and 12 hours, respectively, for LLB and LLA. By this point, the plasma ascorbic acid levels for the powdered vitamin C groups had already reached baseline levels.
This is interesting because whereas the vitamin C concentration in the blood of the liposomal group were still increasing, the other two groups had already reached their peak. Thus, not only did LLA and LLB result in much higher plasma ascorbic acid levels (Cmax), but they also stayed high for much longer.
A further point to note is that while all the study groups reached baseline plasma levels by the end of the study period, the group that received our liquid liposomal formulation had still not reached baseline levels.
3. When we compared the two liquid liposomal supplement groups, it was found that our formulation (LLA), resulted in significantly higher plasma ascorbic acid levels fromm hour 10 through hour 20. This means that our liquid liposomal supplement continued to slowly release vitamin C into the bloodstream long after the competitor’s supplement.
4. Finally, when we compared the bioavailabilities of the four study groups, we found that our liquid liposomal formulation was 12.17-times more bioavailable than the non-liposomal supplement.
Most interesting though, was that our formulation was also 21.64-times more bioavailable than the powdered liposome formulation.
What does all this mean?
Our study suggests that the amount absorbed from a single dose of our liposomal vitamin C formulation is higher compared to all the tested products. This could basically mean that food supplements, like vitamin C, that were limited by their poor absorption in the past can now also become powerful tools thanks to liposomal technology.
We have also often been asked why we insist on producing liposomal formulations in the liquid form. This study proves our case against powdered liposomes.
- [Online] EU Register of nutrition and health claims made on foods (v.3.6). Accessed on 25.10.2022
- [Online] Vitamin C: NIH Fact Sheet for Health Professionals. Accessed on 25.10.2022
- [Online] Dietary Reference Values for the EU. Accessed on 25.10.2022
- [Online] Passwater RA. Oral High-Dose Vitamin C for Major Diseases. WholeFoods magazine. 2017.
- Prantl L, Eigenberger A, Gehmert S, Haerteis S, Aung T, Rachel R, Jung EM, Felthaus O. Enhanced Resorption of Liposomal Packed Vitamin C Monitored by Ultrasound. J Clin Med. 2020;9(6):1616.