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Quest Vitamins LTD,
8 Venture Way,
Aston Science Park,
B7 4AP.

Tel: 0121 359 0056
Fax: 0121 359 0313
Registered in England No. 2530437

Issue # 64: You are not what you eat, but what you absorb!

Piperine is a pungent alkaloid present in Piper nigrum Linn and Piper longum Linn and is thought to be the active ingredient found in black pepper. This discovery has prompted numerous scientific studies into piperine?s possible therapeutic effects with the principle effect seeming to be as a bioavailability enhancer. The natural concentration of piperine in black pepper is around 5-9% but to potentiate the absorption enhancing properties of this phytonutrient, a more concentrated form is required.

 A recent study found that piperine, extracted from black pepper, caused an increase in bioavailability for ions and macromolecules and this might be of pathophysiological importance with respect to food allergy and intolerance. (1)  

This study was designed to investigate and understand the absorption dynamics of piperine in the intestine on oral absorption, using human intestinal cells as an experimental model. The results suggested that piperine is absorbed very fast across the intestinal barrier and it may modulate membrane dynamics due to its easy partitioning thus helping efficient permeability across the intestinal wall. (2)  

Another study also demonstrated that piperine may have the ability to increase the bioavailability of certain nutrients. This study used coenzyme Q10 as the nutrient and the results showed that piperine did increase plasma levels of coenzyme Q10 and it is thought that this bioenhancing mechanism is non-specific and possibly based on its description in the literature as a thermonutrient. (3)

A recent study was designed to investigate the mode of action regarding piperine?s bioenhancing effect. The results showed that piperine may be inducing alterations in membrane dynamics and permeation characteristics, along with induction in the synthesis of proteins associated with cytoskeletal function, resulting in an increase on the small intestine absorptive surface, thus assisting efficient permeation through the epithelial barrier. (4)  

The bioenhancing effects of piperine have been demonstrated in several other studies which show that piperine can improve the absorption of many nutrients. These include: Vitamin C, Selenium, Beta-carotene, vitamin A, vitamin B6, Coenzyme Q10. This action is thought to be non-specific which is demonstrated by the range of nutrients which had improved absorption. (5)

  1)      J Nutr 1998 Mar; 128(3):577-812)      Indian J Exp Biol 1998 Jan; 36(1):46-503)      Mol Cell Biochem 1998 Dec; 189(1-2):113-84)      0955-2863 2003 Feb 1; 11(2): 109-1135)      Nahrung 2000 Feb; 44(1): 42-6 

Fish Consumption and Heart Health

The consumption of fish decreases the risk of sudden death but heart rate is positively associated with the risk of sudden death. A recently published study explored the relationship between fish consumption and heart rate.  9785 men (age 50 - 59) were recruited for a cross-sectional analysis that was conducted over a period of two years between 1991 and 1993. The subjects were assigned to one of four groups, depending on the frequency of their fish consumption. Heart rate and CHD risk factors were compared among the four categories. 

The results showed that fish consumption is inversely related to heart rate and it was concluded that this might explain the lower risk of sudden death among fish consumers.  

Circulation. 2003 Aug 11.

Mutivitamin supplements and diabetes-associated birth defects

The frequency of characteristic birth defects, especially those affecting the heart and nervous system, is higher than average among children of diabetic mothers. It has been proposed that these defects can be attributed to an increased occurrence of free radicals resulting from an elevated maternal blood sugar level.Correa et al recently used data from the Atlanta Birth Defects Case-control Trial to investigate the effects of supplementation with a multivitamin during the three months prior to conception and the first three months of pregnancy on the rates of defects in newly born children of diabetics.  

The results of the data-analysis showed that the rate of defects among offspring of diabetic mothers who had not used multivitamin supplements was 400% higher than those born to non-diabetic mothers who had not used multivitamins. Children of diabetics who had used supplements did not have an increased rate of birth defects compared to those of non-diabetics. 

Pediatrics 111, 1146-1151, 2003

Tomatoes and cardiovascular health

Diet is a major influence on the development of cardiovascular disease, the commonest cause of death in most industrialised countries. Tomatoes are widely produced and consumed, they are also a rich source of lycopene, beta carotene, folate, potassium, vitamin C, flavonoids and vitamin E.

A recent review examined the role of tomatoes in protecting against heart disease. It was reported that many of the nutrients present in tomatoes may function individually or in concert to protect lipoproteins and vascular cells from oxidative damage, a major step in the development of atherosclerosis. Other reported benefits included the reduction of LDL cholesterol, homocysteine, platelet aggregation and blood pressure.  Crit Rev Food Sci Nutr. 2003;43(1):1-18.

Carotenoids, vitamin E and sarcopenia

It is believed that oxidative stress may play a role in the pathogenesis of sarcopenia, which is defined as the age-related loss of muscle mass and strength. A recent study investigated the relationship between dietary antioxidants and sarcopenia, by determining whether dietary carotenoids and alpha-tocopherol were associated with sarcopenia, as indicated by low grip, hip, and knee strength.

Cross-sectional analyses were conducted on 669 non-disabled to severely disabled community-dwelling women (aged 70 to 79 years) who participated in the Women's Health and Aging Studies. Plasma carotenoids and alpha-tocopherol were measured. Grip, hip, and knee strength were measured, and low strength was defined as the lowest tertile of each strength measure.

 The results showed that higher carotenoid and alpha-tocopherol status were both independently associated with higher strength measures and it was concluded that this data support the hypothesis that oxidative stress is associated with sarcopenia. 

Aging Clin Exp Res. 2003 Dec;15(6):482-7.

Is fish really good for the brain?

Over the last few months the apparent positive effects of fish oils and essential fatty acids on the brains of children have been the focus of much media attention. However, a recent study conducted in the Netherlands investigated the relationship that fatty acid and fish consumption has with mental performance in middle aged adults. 

It was found that the marine omega-3 polyunsaturated fatty acids EPA and DHA were associated with a reduced risk of impaired overall mental function and speed. The results showed a similar relationship for fatty fish consumption. Higher dietary cholesterol and saturated fatty acid intakes were associated with an increased risk of impaired memory and mental flexibility (defined as higher order information processing). 

It was concluded that fatty fish and marine omega-3 PUFA consumption were associated with a reduced risk, and intake of cholesterol and saturated fat with an increased risk of impaired mental function in the middle-aged population studied. 

Neurology. 2004 Jan 27;62(2):275-80. 

Antioxidant supplementation and Alzheimer?s disease 

It has been suggested that antioxidants may protect the ageing brain against oxidative damage associated with pathological changes of Alzheimer disease and a recent study set out to test this hypothesis. The relationship between the use of antioxidant supplements and the risk of Alzheimer?s disease was examined in a cross-sectional and prospective study involving 4740 subjects aged 65 years or older. 

From the results, the authors concluded that the use of vitamin E and C supplements in combination was associated with a reduced prevalence and incidence of Alzheimer?s disease and that antioxidant supplements merit further study as agents for the primary prevention of Alzheimer?s disease.

 Arch Neurol. 2004 Jan;61(1):82-8.

A to Z of Nutrition: Vitamin E

Vitamin E occurs as a range of compounds in nature: alpha, beta, delta and gamma tocopherol and tocotrienols.

What does it do?

Vitamin E is a very important antioxidant. Its properties are vital in the membranes of tissues that have a high concentration of polyunsaturated fats (PUFAs), such as in the brain, nervous system and lungs.

As an antioxidant nutrient, vitamin E helps protect PUFAs and other fatty substances such as cholesterol from oxidation caused by free radicals.

Vitamin E also has an important neurological role and prevents degeneration of the nerves and muscles.

Vitamin E may also play an important role in wound healing and stimulating the immune response.

What are the deficiency signs?

Deficiency of vitamin E does not lead to any specific disease in the short term, but chronic insufficiency of vitamin E is thought to be a contributory factor in cancer and heart disease.
In children, fat malabsorption can lead to a deficiency of vitamin E characterised by abnormal red blood cell development.

Is it toxic?

Levels over 800mg vitamin E (d-alpha tocopherol) have occasionally been associated with such symptoms as: fatigue, nausea, mild gastrointestinal problems, palpitations and transient blood pressure increase. Such symptoms are reversible.

Who should supplement?

Vitamin E supplements are advised in individuals who have fat malabsorption problems.
To date, these are some of the research-based conditions that vitamin E supplements may help prevent:

Heart conditions

Circulatory disorders

Fibrocystic breast disease

Blood platelet aggregation (e.g. in susceptible women on the contraceptive pill)

Vitamin E may also be used as a nutritional therapy in the following conditions:
Premenstrual menstrual syndrom

Post-operative wound healing

Poor circulation, variciose veins etc.

Skin complaints
Intake levels: milligrams (mg)

RDA: 10

Upper safe levels:
800 (Short term)
800 (long term)

Which foods?

Milligrams (mg)/100g
Safflower oil                         97
Sunflower seeds, raw            74
Sunflower oil                        73
Almonds                               37
Mayonnaise                          19
Wheatgerm                           17


1.    Health Essentials vitamin guide: 1994
2.    Vitamin and mineral safety council for responsible nutrition: 1997

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