Nutrient digestion and absorption is necessary for the survival of living organisms and has evolved into the complex job of the gastrointestinal (GI) system. Most people assume that their GI tract will work properly to digest their food and use the nutrients for bodily functions.
But some nutrients, particularly water-soluble ones, are poorly absorbed in the body. Humans cannot synthesise water-soluble vitamins and they need to be obtained from the diet.
Interference with absorption, which occurs in a variety of conditions (e.g. congenital defects in the digestive or absorptive system, intestinal disease/resection, drug interactions and chronic alcohol use), leads to the development of deficiency (and sub-optimal status) and results in clinical abnormalities.1
Fat-soluble delivery methods, such as liposomes and phytosomes, make nutrients more accessible by the body. Phytosomes and liposomes both improve the absorption of poorly water-soluble substances using phospholipids, but their structure and where the substance is stored is different (see diagram).
Key features and benefits of both phytosomes and liposomes are outlined in the table.
|Phytosome features||Liposome features|
|Formulated using non-GMO soy lecithin, active molecules are anchored through bonds to the polar heads of phospholipids. Ratio of phospholipid to phytoconstituent is 1:1 or 2:1, depending on the substance.||Formulated using sunflower lecithin, active molecules are dissolved and formed spontaneously in the cavity or in the layers of the membrane; no bonds are formed.|
|A chemical reaction embeds the active compounds into the phospholipid membrane; does not require adjuvants/PEGs.||Small liposomal vesicles (SUVs) are the results of refined chemistry and high-shear equipment and refined chemistry to ensure particle sizes range between 20nm-100nm. SUVs are more efficient at intracellular delivery of encapsulated compounds.|
|The water-soluble constituents of plant extracts (flavonoids and terpenoid) have the affinity to bind directly with phosphatidylcholine.||Vehicles for transporting substances into the body via passive absorption across mucous membranes. When liposomal particles are small enough, direct absorption occurs in the mouth, bypassing the digestive system for rapid and unhindered absorption.|
|Affinity and rapid exchange of phospholipids from the phytosome to cellular membranes.||Absorbed liposomal particles fuse with cell membranes to deliver encapsulated compounds intracellularly.|
|Improves the absorption and bioavailability of poorly available active ingredients, mimicking the effect of a fatty meal.||Nano-sized vesicles that demonstrate the ability to cross the blood-brain barrier, deposit their cargo intracellularly and contribute to the lymphatic circulation of therapeutic compounds.|
|Administered orally and absorbed via digestive tract.||Administered orally for transmucosal absorption in the mouth, therefore are better taken in a liquid form and held in the mouth.|
|A patented process developed by Indena.||A patented process developed by Quicksilver Scientific.|
A number of nutrients are available in liposome and phytosome forms and have been clinically trialed with successful results, showing improved absorption of the nutrients.
A liposomal preparation of glutathione (GSH) was investigated for its ability to replenish intracellular GSH and provide neuroprotection in an in vitro model of Parkinson's disease. Over 4 hours, liposomal-GSH or non-liposomal-GSH was given and liposomal-GSH was 100-fold more potent. No toxicity was observed with the liposomal preparation at 200-fold the half maximal effective concentration
(EC50) for repletion. These findings indicate that glutathione supplied in a liposomal form holds promise as a potential therapeutic for neuronal maintenance.2
Other studies have found that treatment with a liposomal GSH resulted in replenishment of reduced GSH (rGSH) in people with HIV3 as well as children diagnosed with an autism spectrum disorder (ASD), who have significantly lower levels of GSH than typically developing children.4
Oral vitamin C administration is typically less effective than intravenous, due in part to inferior vitamin C bioavailability. A study showed that 4g of vitamin C via oral, oral liposomal or intravenous delivery indicated that oral delivery encapsulated in liposomes produces circulating concentrations of vitamin C that are greater than unencapsulated oral delivery but less than intravenous administration.5
Topical application of liposomal vitamin C has also shown to overcome the barrier of the stratum corneum, resulting in improve skin penetration of vitamin C into the dermis, preventing skin photodamage.6
Silybin is the primary and most active component of Silybum marianum (milk thistle), but it’s action is limited by poor oral bioavailability. The Siliphos® Silybin Phytosome® form of silybin improves the oral bioavailability of silybin; it is more rapidly absorbed (at least four times more completely) compared to a standardised silymarin extract, reaching the liver and appearing in the bile within a few hours. Standard milk thistle extract recommended dosing is 420mg daily to achieve benefit, while Siliphos® Silybin can produce benefit as low as 120mg per day.7,8
Liposome and phytosome forms of nutrient supplements improve the bioavailability of nutrients that often have poor uptake. These fat-soluble delivery methods also provide benefits to those with digestive or intestinal conditions that may further impair the absorption of nutrients.
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1. Siad HM. Intestinal absorption of water-soluble vitamins in health and disease. Biochem J 2011;437(3):357-372.
2. Zeevalk GD, Bernard LP, Guilford FT. Liposomal-glutathione provides maintenance of intracellular glutathione and neuroprotection in mesencephalic neuronal cells. Neurochem Res 2010;35(10):1575-1587.
3. Morris D, Guerra C, Khurasany M, et al. Glutathione supplementation improves macrophage functions in HIV. J Interferon Cytokine Res 2013;33(5):270-927.
4. Kern JK, Geier DA, Adams JB, et al. A clinical trial of glutathione supplementation in autism spectrum disorders. Med Sci Monit 2011;17(12):CR677-CR682.
5. Davis JL, Paris HL, Beals JW, et al. Liposomal-encapsulated ascorbic acid: Influence on vitamin C bioavailability and capacity to protect against ischemia-reperfusion injury. Nutr Metab Insights 2016;9:25-30.
6. Serrano G, Almudéver P, Serrano JM, et al. Phosphatidylcholine liposomes as carriers to improve topical ascorbic acid treatment of skin disorders. Clin Cosmet Investig Dermatol 2015;8:591-599.
7. Kidd P, Head K. A review of the bioavailability and clinical efficacy of milk thistle phytosome: A silybin-phosphatidylcholine complex (Siliphos). Altern Med Rev 2005;10(3):193-203.
8. Li W, Gao J, Zhao HZ, et al. Development of a HPLC-UV assay for silybin-phosphatidylcholine complex (silybinin capsules) and its pharmacokinetic study in healthy male Chinese volunteers. Eur J Drug Metab Pharmacokinet 2006;31(4):265-270.