GB2313545A - A lipid binding composition comprising a chitin derivative and ascorbic acid - Google Patents

Abstract

A food additive or pharmaceutical composition comprises a chitin derivative having a free amino group, preferably chitosan, ascorbic acid and a swelling agent. The composition may be presented in a gelatine capsule. The swelling agent, preferably an organic acid such as citric or lactic acid, enhances the lipid binding capacity of the chitosan matrix in the gut.

Description

LIPID BINDING FOOD ADDITIVE The present invention relates to a lipid binding fat additive. The use of Chitosan as a lipid binding food additive has been described in US-A-4223023. Chitosan is a partially or fully deacetylated Chitin. Chitin is a natural glucose-like polymer usually extracted for the exoskeletons of arthropods, such as lobsters, crabs etc. Chitosan is conventionally prepared by the alkaline deacetylation of Chitin with concentrated sodium-hydroxide at an elevated temperature. The degree of deacetylation can be adjusted by suitable variation of the reaction steps so that the degree of acetylation is usually between 65% and 95%.

It has been found that Chitosan particularly is capable of binding to various fatty acids to form a complex salt and to do so in the gastro-intestinal tract. Further the binding effect on free lipids is preferential to any other form of binding and accordingly this binding propensity prevents uptake of the lipids in the intestine.

It has also been found for example in Bioscience, Biotechnology and Biochemistry 58(9)1994, pages 1617 to 1620 that Chitosan may be utilised in the presence of an antioxidant such as ascorbic acid to increase lipid binding.

Lipid binding is increased even more in the presence of defined plant extracts and/or a biologically acceptable swelling agent for Chitosan or other active Chitin derivative.

The invention thereby provides means whereby fat may be elimated efficiently with body waste rather than taken up in the gastrointestinal tract.

Low fat diets are often desirable in the treatment of dysfunctions of the gall bladder and in the treatment of obesity, gastro-intestinal dysfunctions or arterial disease.

These conditions predicate removal of fat from the diet, especially of bile acids, cholesterol and other fatty acids.

Accordingly the above identified compositions have a pharmaceutical as well as an essentially cosmetic effectiveness.

The Bioscience, Biotechnology and Biochemistry, reference alluded to above, reveals the results of feeding rats inter alia with Chitosan and ascorbic acid or various organic acids such as lactic or citric acids. Although the inventor of this application does not wish to be tied to any particular mechanism it is believed that the method described for decreased digestability resultant from Chitosan and ascorbic acid may be explained as follows: Gastric acid soluble Chitosan when mixed with dietary lipids (fat) in the stomach is emulsified in part by the ascorbic acid. When the products of digestion empty from the stomach into the small intestine they contact pancreatic juice at an alkaline pH whereupon oil droplets become embedded in a gelled Chitosan matrix. In this state the matrices so formed are too large for absorption by the gut and hence are excreted.

We have now discovered that the Chitosan/ascorbic acid admixture is more effective if an acidic swelling agent such as citric or lactic acid or an appropriate salt is used in admixture. The effect of these is thought to be that the swelling of the Chitosan in the presence of ascorbic acid is enhanced by such swelling agents such that the Chitosan matrix swells in response to the alkaline pH to increase the surface active area so that lipid droplets are more readily adsorbed thereto.

We have particularly found that the particle size of the admixed Chitosan should be no more than 150pm but preferably larger than 50pm and more preferably 100cm. At this size the Chitosan reacts more effectively with the ascorbic acid and the swelling agent such as citric acid to form a gel mentioned above. Since Chitosan is expensive the addition of the swelling agent enables a relative reduction of the amount of Chitosan for a given result.

Organic acids such as citric acid have the extra effect of imparting a "sated" feel to the recipient as a result of the swelling effect which tends to reduce intake.

According therefore to the present invention there is provided a lipid binding food additive comprising in admixture a natural or synthetic Chitin derivative provided with free amino groups capable of gastro-intestinal lipid binding and ascorbic acid or an active derivative thereof, characterised by a biologically acceptable swelling agent for said admixture selected from an organic salt or acid.

Preferably organic salt is citric or lactic acid or an active salt thereof. The particle size of the Chitosan, and preferably of the admixture, is in the range of 50jim to 150m.

It is also preferred that the ratio of Chitosan to the ascorbic acid is in the range of 3 to 1 to 10 to 1, or preferably 5 to 1. Additionally another organic or inorganic acid such as Malic acid may be added to increase the acidity of the stomach particularly in the older patient. The Chitin derivative is preferably Chitosan as described above. The admixture is further improved by a source of indoles such as those found in Brassica extracts The indoles may be provided additionally by at least one of Psyllium husks (Plantago-ovata), Konjac-Glucomannan and a Phyto-nutrient complex comprising a cruciferous vegetable concentrate. Such a concentrate may comprise one or more Brassica selected for example from broccoli, kale and mustard extracts.

The food additive is preferably disposed in a biologically acceptable carrier therefor. It may for example be encapsulated in gelatine to form an aqueous capsule.

In a further aspect of the invention there is provided a pharmaceutical composition comprising a lipid binding food additive as herein before set forth. It has been found experimentally that the use of Chitosan alone in compositions in accordance with the present invention but without ascorbic acid leads to a lipid binding of about four times the weight achievable with pure Chitin alone. The utilisation of ascorbic acid and the extra additives approximately doubles this value to 8 or 9 times by weight. The addition of ascorbic acid to Chitosan but in the absence of the extra additives leads to increase of lipid binding of only about 6 times whereas the addition of the biologically acceptable swelling agent such as citric acid raises this to the 7 or 8 times given above.

The invention will now be described by way of example only as follows: Example - A lipid binding food additive is made up as follows:- 250 mg Deacetylated Chitin derivative 100 mg Plantago-ovata (Psyllium husks) 50 mg Konjac-Glucomannan 50 mg Phyto-nutrient complex comprising broccoli, kale and mustard seed 25 mg Erythorbic acid 25 mg Ascorbic acid (to 500 mg) Gelatine water to make a capsule of 500 mg. The capsule is such as to be broken down in the acid conditions of the stomach on oral ingestion.

Groups A, B, C and D were produced by suitable amendment of this composition.

Example 2 - A number of healthy volunteers were asked to refrain from eating for twelve hours and then given a gentle enema to evacuate the bowels. Each volunteer then received 150 g of a diet high in triglycerides whereupon the volunteers were divided into four groups: Group A received the diet and a placebo, Group B received the diet and the chitin derivative alone, Group C received the diet, the chitin derivative and the anti-oxidant, and Group D received the chitin derivative, the anti-oxidant and the additional plant derived material.

Each group was instructed to take two capsules with 225g of water before or during ingestion of the diet. The eliminated waste from each volunteer was collected, dried and analysed for triglyceride content. Other fats where not analysed at this stage to simplify proceedings.

It was found that whereas in Group A relatively little triglyceride was to be found after ingestion, in Group B about four times the weight of the original chit in derivative was to be found. In Group C this rose to between six and seven times the weight whereas in Group D the full eight times by weight of triglyceride was found.

Example 3 - In another aspect of the invention a second food additive prepared as follows: 250 mg Deacetylated Chitin-Biopolymer 110 mg Psyllium Husk Powder (Plantago-ovata) 60 mg Konjac Glucomannan 20 mg Broccoli Extract 60 mg L-Ascorbic Acid 100 mg Gelatine as a capsule with water to 600 mg Example 4 - A lipid binding food additive was made up as follows:- Particle Size Chitosan powder - less than l50jm 250mg L-ascorbic acid Citric acid 30mg Malic acid 15mg Broccoli extract (indoles) 100mg Capsule shell (beef) gelatine/water 100mg Groups E, F, G, H and I were then produced by suitable amendment of the above.

Example 5 - A number of healthy volunteers were again asked to refrain from eating for 12 hours and then gently evacuated with an enema. Each volunteer then received 150g of a diet high in triglycerides and was assigned to one of five groups E to I.

Group E received diet + placebo, Group F received diet + Chitosan alone, Group G received diet + Chitosan + Ascorbic acid, Group H received diet + Chitosan + Ascorbic acid + Citric acid, and Group I received diet + Chitosan + Ascorbic acid + Citric acid + a source of indoles.

Each group was instructed to take two capsules with 225mg of water before or during ingestion of the diet. Faecal waste from each volunteer was collected, dried and analysed for triglyceride content to simplify analysis.

The results achieved were as follows: Food Intake Group E 150g + 250mg placebo + Water Group F 150g + 250mg Chitosan + Water Group G 150g + 250mg Chitosan & 50mg Ascorbic acid + Water Group H 150g + 250mg Chitosan, 50mg Ascorbic acid & 30mg Citric acid + Water Group I 150g + 250mg Chitosan, 50mg Ascorbic acid, 30mg Citric acid, 15mg Malic acid & Smg broccoli extract + Water The results in terms of percentage faecal lipid retention were as follows in mg/g: E - 8% to 11% F - 30% to 35% G - 48% to 55% H - 62% to 69% I - 64% to 71% It was further found that protein levels were not significantly effected.

The invention provides therefore a lipid binding food additive and pharmaceutical composition comprising the same.

Claims (8)

1. A lipid binding food additive comprising in admixture a natural or synthetic Chitin derivative provided with a free amino group capable of gastro-intestinal lipid binding and ascorbic acid or an active derivative thereof, characterised by a biologically acceptable swelling agent for said admixture selected from an organic acid or salt.

2. An additive according to Claim 1 wherein the organic acid or salt is citric or lactic acid or an active salt thereof.

3. An additive according to either of Claims 1 or 2 where the particle size of the admixture is in the range of 50jim to 150Am.

4. An additive according to any preceding claim wherein the ratio of Chitin derivative to ascorbic acid is in the range of 3 to 1 and 10 to 1.

5. An additive according to Claim 4 wherein the additive is Chitosan and the ratio of Chitosan to ascorbic acid is about 5 to 1.

6. An additive according to any preceding claim wherein an organic or inorganic acid is added to the admixture to increase acidity in situ.

7. An additive according to any preceding claim further comprising a source of indoles.

8. A pharmaceutical composition comprising a lipid binding food additive as claimed in any one of claims 1 to 7.