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Functional foods in Angiology and Vascular Surgery
(Portuguese PDF version)

Douglas Faria Corrêa Anjo¹

1. Specialist in Angiology and Vascular Surgery, SBACV/AMB. Specialist in Nutrology, ABRAN/AMB.

Correspondence:
Douglas Faria Corrêa Anjo
Rua Guilherme Cristiano Wackerhagem, 405
CEP 89253-415 - Jaraguá do Sul, SC
E-mail: Dcanjo@netuno.com.br

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ABSTRACT

Functional foods are defined as products containing some biologically active substance that, when added to usual diet, triggers metabolic or physiologic processes, resulting in prevention of diseases and maintenance of health. The objective of this study is to provide angiologists and vascular surgeons with up-to-date information on this topic. The major groups of bioactive substances and their indications are presented. Being a recent field of study, further research is necessary in order to determine the beneficial effects of bioactive substances, as well as the toxic amounts and long term side effects.

Key-words: food, diet, vascular surgery.
Palavras-chave: alimentos, dieta, cirurgia vascular.

J Vasc Br 2004;3(2):145-55

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Tonight, at the dinner table, when you will be about to begin to serve yourself, you will be composing a self-portrait. Your parents, your income, your social rank and your religion are reflected in the food that you eat, avoid, detest or cannot afford. And, why not, the how much you care about your health?¹

Nowadays, there are few legal publications that do not present articles about recipes, diets or the latest "miraculous" release to improve or keep health.

This work aims at providing angiologists and vascular surgeons with subsides that will help them to better advise their patients when defining their dietary habits, mainly regarding the so-called functional foods.

Due to the wide spreading, by the general press, of the relationship between diet and health, the western society concern about food has increased in an exponential way.

A huge amount of new products, which are supposed to provide health, has been released by the food industry day after day.

Our objective is to help our colleagues who act on the vascular area to assess these products.

Functional foods are defined as any food substance or component that brings benefits to health, including prevention and treatment of diseases. These products may range from isolated nutrients, biotechnology products, dietary supplements, and genetically produced foods to processed and plant-derived foods.²

Some parameters should be taken into account regarding functional foods. According to Borges,³ they should have a metabolic or physiologic effect that contributes to physical health and to reducing the risk of developing chronic diseases. In this sense, they should be part of the habitual diet and provide positive effects, obtained from non-toxic amounts. These effects should persist even after the ingestion has been suspended. The functional foods are not expected to treat or cure diseases; their role is, therefore, to reduce the risk of contracting diseases.

THE ORIGIN OF FUNCTIONAL FOODS

The low incidence of diseases in some groups of people called our attention to their dietary habits. The Eskimos, with their fish/seafood-based diet, rich in omega-3 and 6, have a low rate of heart problems; this is also true for the French, consumers of red wine; finally. Oriental countries, with high consumption of soy, rich in phytoestrogen, present low rates of breast cancer. In these countries, the habit of consuming fruits and vegetables also results in reduced rates of coronary diseases and cancer, as shown by epidemiologic data.

Functional foods belong to a new concept of food released in Japan in the Eighties through a government program which aimed at developing healthy foods for a population that was getting older and presented higher life expectancy.⁴

Added to this fact, there was also the perspective of high financial returns, therefore, it was necessary for the food industry to invest in research, development and marketing of new products.

These new products and their actual efficiency of preventing diseases are issues that are constantly debated among the scientific community.

SYNONYMY

In addition to the name "functional food", angiologists may find other terms to designate these foods. Introduced in 1989, the term "nutraceutic" was created in an attempt to differentiate functional foods from medicines.

In English, functional foods are also called foods for special dietary uses, medical foods, fortified foods, dietary supplements, health foods or novel foods.

In what concerns medical foods, assertions referring to specific diseases are allowed, and this is what distinguishes them from functional foods. Fortified foods, to which are added some substance, may be considered functional if essential nutrients were added to the common foods to provide health benefits. Dietary supplements differ from functional foods because they are not able to replace a daily diet, and their forms of presentation are closer to that of medicines.⁵

BIOACTIVE COMPOUNDS IN FUNCTIONAL FOODS

Phytochemicals

Phytochemicals are substances found in fruits and vegetables that may be daily ingested in certain amounts. They have a potential to modify human metabolism, preventing cancer and other degenerative diseases (American Dietetic Association, ADA).⁶

Some foods present these substances in larger amounts, such as citric fruits, garlic, cabbage, soy, ginger, onion, tomato, eggplant, broccoli, cauliflower, oat, chive, mint, oregano, cucumber, parsley and saffron.⁷

The average intake of phytochemicals ranges from 1 to 4.5 g/day in a diet that includes fruits, vegetables, tea and red wine. Some of the most important phytochemicals are the terpenoids (carotenoids, limonoids, phytosterols and saponins), the nitrogen compounds (glucosinolates) and the phenolic metabolites (phenolic acids, polyphenols and flavanoids).

Terpenoids

Terpenoids are found in vegetables, soy and grains, and have antioxidant activity and interaction with free radicals by dividing their wide carbon chain in lipid membranes. Some terpenes are naturally found in grains and are related to reduced risk of cancer, as shown in some in vivo studies.

Carotenoids are a highly-pigmented type of terpene (yellow, orange and red) that is found in fruits and vegetables. A total of 1,600 chemical compounds are identified in two classes of molecules: carotenes (beta-carotene found in carrots and African oil palm; lycopene, found in tomatoes and water melons; lutein, found in green vegetables), and xanthophylls (zeaxanthin, cryptoxanthin and astaxanthin). The first class has the ability to protect against gallbladder, womb, prostate, lung and colorectal cancer. The second offers protection against other antioxidants. Some terpenes found in citric fruits, the limonoids, have a chemotherapeutic action. In the same class of substances, we find the phytosteroids (phytosterin, saponin and beta-sitosterol), which are similar to cholesterol and compete for their absorption in the bowels, reducing the serum or plasma levels of total and low-density cholesterol.⁸

Nitrogen compounds

The consumption of foods that are rich in nitrogen compounds helps protect against carcinogenesis and mutagenesis. Glucosinolates contain sulphur and are present in foods such as broccoli, cauliflower, radish, heart of palm and caper; they activate detoxification enzymes found in the liver.⁹

Phenolic metabolites

The most important phenolic metabolites are the phenolic acids (hydroxybenzoic and hydroxycinnamic acids), polyphenols and flavanoids. The bitter and adstringent flavor of most foods and drinks that contain these substances is due to the presence of phenolic compounds. High-molecular-weight tannins are present in wines and convey the astringent flavor. Low-molecular weight tannins have a tendency to a bitter flavor.¹⁰

Flavones, flavanones, flavanoids, catechins and anthocynins form the flavanoid group. They protect against LDL-cholesterol oxidation by reducing free radicals, metallic ion chelation and alpha-tocopherol regeneration. They also act against free radicals, allergies, inflammations, ulcers, viroses, tumors and hepatotoxins, and inhibit red cell aggregation, reducing cardiopathies, thromboses and estrogen synthesis.⁸

Anthocyanidins are water-soluble flavanoids considered antioxidants in vitro, and may present antioxidant and antimutagenic action in vivo as well. Catechins, flavanoids, anthocynins and phenolic acids are present in wine and have an antioxidant action. The catechin that is present in green tea is responsible for the protection against cardiovascular atherosclerotic disease.

A subclass of flavanoids is the isoflavones, which act against cancer, diabetes, osteoporosis, cognitive deficiency, cardiovascular diseases and menopause-related problems. Their structure and activity is similar to that of the human estrogen, and they are known as phytoestrogen. Cells that have phytoestrogen receptors may be influenced by these molecules, and, therefore, are used in the treatment of menopause symptoms. Epidemiologic studies have shown that populations who consume soy products regularly present a lower incidence of colon, breast and prostate cancer. According to the FDA, the recommended amount of isoflavone/day in the form of aglycone is of 30-60 mg.¹¹

Fatty acids

This group is composed of polyunsaturated fatty acids, with emphasis to the omega-3 and 6 series, found in cold-water fish (salmon), vegetal oils, linseed, walnuts and some types of vegetables. They are related to the prevention of cardiovascular diseases through the reduction of triglyceride and cholesterol levels, increasing blood flow and reducing blood pressure.¹²

Oligosaccharides e polysaccharides

Oligosaccharides and polysaccharides are known as fibers. The effects of their consumption are reduction in blood cholesterol levels and decreased risk of developing cancer. This is due to three factors: ability to retain toxic substances ingested or produced in the gastrointestinal tract during digestion; reduced bowel transit time, promoting fast elimination of stools and reduced time of contact between bowel tissues and mutagenic/carcinogenic substances; and formation of protective substances through the bacterial fermentation of compounds.¹³

PREBIOTIC AND PROBIOTIC FOODS

In relation to the interference of functional foods with the intestinal flora, three groups can be established: prebiotic, probiotic and symbiotic foods.

Prebiotic foods

Prebiotic foods are complex carbohydrates (fibers) that are resistant to the actions of salivary and intestinal enzymes. When they reach the colon, they have beneficial effects on the colonic microflora.

Prebiotic foods do not suffer hydrolysis or absorption in the small intestine and change the colonic microflora making it healthier.^14-16

Substances such as lactose, xylitol, inulin and fructooligosaccharides present the following effects: changes in the intestinal transit, reduction of toxic metabolites; prevention of diarrhea or intestinal obstipation, changes in the colonic microflora; decrease in the risk of developing cancer; decreased levels of cholesterol and triglycerides; control of blood pressure; increased production and bioavailability of minerals; reduction in the risk of developing obesity and insulin-dependent diabetes; and reduction in lactose intolerance.¹⁷

Fructooligosaccharides are the only products currently recognized and used as food ingredients. They are industrially produced through the hydrolysis of inulin by the inulase enzyme, via saccharose. These substances are physiologically similar to fibers, but do not increase the solution viscosity, do not alter the mixture of food components in the small intestine and do not seem to bind to bile salts. Their main role is to stimulate the intestinal growth of colonic bifidobacteria, which act suppressing the putrefaction activity carried out by other bacteria, such as Escherichia coli, Streptococcus fecalis, Proteus and others, also increasing the volume of fecal matter in the small intestine.

Daily doses of 4-5 g are enough to stimulate the growth of bifidobacteria, at a caloric amount of 1.5 kcal/g.³

Inulin is either extracted from endive roots or produced with saccharose. Fructooligosaccharides are present in garlic, tomatoes, onions, bananas, artichokes, rye, barley, wheat, honey and beer.³

Probiotic foods

Probiotic foods are dietary supplements that contain bifidobacteria or other bacteria that enhance intestinal balance through the colonization of the bowel by other species, aiming at controlling cholesterol, diarrhea and the risk of developing cancer. They have the role of stimulating the immune system and altering the microbial mechanism.¹⁵

Probiotic are expected to have some characteristics, such as being usual inhabitants of the organism with fast reproduction, producing antimicrobial substances and resisting throughout the time elapsed between production, sale and consumption of the product, so that they can reach the bowel alive.¹⁶

The inhibitory mechanism of pathogenic bacteria is related to the production of bactericidal substances, competition for nutrition and alteration in the microbial metabolism. The most important probiotic foods are Lactobacillus acidophilus, casei, bulgaricus, lactis and plantarum, Streptococcus thermophilus, Enterococcus faecium and fecalis, Bifidobacterium bifidum, longum and infantis.

Probiotics may be part of industrialized foods (such as fermented milk products). They also may be found as powders or tablets.

The balanced combination of prebiotic and probiotic foods, with functional characteristics of both groups, is what defines symbiotic foods.

Table 1 shows a brief presentation of active compounds of functional foods, their sources and effects on the body.

Table 1 - Active compound, physiologic effects and main sources of functional foods

Active compound	Effect	Source
Terpenoids
Carotenoids	Antioxidant and anticarcinogenic activity (womb, prostate, breast, colon, rectum and lung)	Fruits (water melon, papaya, melon, apricot, peach), vegetables (carrot, spinach, pumpkin, broccoli, tomato, taro, rape)
Phytosteroids	Reduction in total and LDL-cholesterol levels	Vegetal oils, seeds, walnuts, some fruits and vegetables
Glucosinolates	Liver detoxification, anticarcinogenic and antimutagenic activity	Broccoli, cauliflower, cabbage, radish, heart of palm and caper
Phenolic agents
Phenolic acids	Antioxidant activity	Fruits (grapes, strawberry, citric fruits), vegetables (broccoli, cabbage, carrot, eggplant, parsley, pepper, tomato, watercress), tea
Flavonoids	Antioxidant activity, reduced risk of developing cancer and cardiovascular disease	Citric fruits, broccoli, cabbage, tomato, eggplant, soy, pumpkin, parsley, walnut, cherry
Isoflavones	Inhibition of estrogen accumulation, reduction of carcinogenic enzymes	Leguminous plants (mainly soy), vegetables
Catechins	Antioxidant activity, reduction in the risk of developing cardiovascular disease	Grapes, red wine, strawberry, green tea, black tea, cocoa
Anthocynins	Antioxidant activity, protection against mutagenesis	Fruits (blueberry, raspberry)
Fatty acids Omega-3 and 6	Reduced risk of developing cancer and cardiovascular diseases, reduction in blood pressure	Cold-water fish, canola oil, linseed and walnuts
Oligosaccharides Polysaccharides	Reduced risk of developing cancer and reduction in cholesterol levels	Fruits, vegetables, leguminous plants, cereals, whole foods
Prebiotics	Regulation of intestinal transit and blood pressure, reduced risk of developing cancer and reduction of total and triglyceride levels, reduced lactose intolerance	Endive root, onion, garlic, tomato, asparagus, artichoke, banana, barley, cherry, rye, oat, wheat, honey
Probiotics	Regulation of intestinal transit, reduced risk of developing cancer and reduction of total and triglyceride levels, immune system stimulation	Yogurt, fermented milk

Adapted from Fagundes & Costa¹⁷

DISCUSSION

The idea of developing this study aroused from several requests of dietary advice from patients concerned about their health. They came to us after being overflowed by intense press coverage about health and diet related issues.¹⁸

We are usually asked to provide information about commercially available foods and new releases. These foods usually claim to have healthy properties for human beings, acting both on the prevention of problems and on the maintenance of health. Is that always true?

An important example is that of milk enriched with omega-3 fatty acids. Since the amount of the compound added to the milk is low, it would be necessary to consume 2 liters of milk/day in order to benefit from the positive effects of this substance.²

The present study aims at providing angiologists and vascular surgeons with resources that will allow them to assess these foods. Being able to evaluate these foods they will better advise their patients or even incorporate the products into treatment.

Fat-free foods, yogurts, isotonic drinks, fortified foods, enriched bread, as well as food sources containing fish oil, rich in omega-3 fatty acids, eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), algae oil enriched with DHA, shark liver oil, in addition to a wide variety of cereals, biscuits and bread rich in fibers, represent an options that are available to the population.

Table 2 shows several functional foods and their main compounds, benefits, and scientific evidence.

Table 2 - Selected functional foods, key components, potential benefits for health, scientific evidence and regulatory classifications

Functional food	Key component	Benefits for health	Scientific evidence	Regulatory classification	References
Low-fat foods (eggs, cheese, snacks, meat, fish, dairy products)	Low total or saturated fat	Reduces risk of developing cancer and coronary disease	Clinical trials	FDA approved health claim	ADA Report, 19996
Foods containing sweeteners instead of sugar (gums, candies, snacks, beverages)	Sweeteners	Reduces risk of damaging teeth	Clinical trials	FDA approved health claim	ADA Report, 19996
Oat, oat bran, oat products	Glucan soluble fiber	Reduces cholesterol levels	Clinical trials	FDA approved health claim	ADA Report, 19996
Low-fat milk	Calcium	Reduces risk of osteoporosis	Clinical trials	FDA approved health claim	ADA Report, 19996
Vegetables and fruits	Vitamins, phytochemicals, fibers	Reduces risk of developing cancer and coronary disease	Epidemiologic/animal studies	FDA approved health claim	ADA Report, 19996
Cereal with folic acid added	Folic acid	Reduces risk of developing neural tube defect	Clinical trials	FDA approved health claim	ADA Report, 19996
Juices, pasta, rice, snacks and other foods containing calcium	Calcium	Reduces risk of osteoporosis	Clinical trials	FDA approved health claim	ADA Report, 19996
Psyllium present in products such as eggs, pasta, bread and snacks	Psyllium fiber	Reduces risk of coronary disease	Clinical trails	FDA approved health claim	ADA Report, 19996
High-fiber grains/cereals	Fiber	Reduces risk of developing certain cancers and coronary disease	Clinical trails	FDA notification Referred to FDMA	ADA Report, 19996
Snacks with echinacea	Echinacea	Immune system	Indirect evidence	FDCA - claim on structure/function	ADA Report, 19996
Gums with phosphatidylserine	Phosphatidylserine	Improves concentration	Indirect evidence	FDCA - claim on structure/function	ADA Report, 19996
Drinks with antioxidant agents	Vitamins E, C and carotene	Improves health in general, especially cardiovascular and immune functions, reduces risk of developing arteriosclerosis	Evidence in humans, epidemiologic/animal studies	FDCA - claim on structure/function	ADA Report, 19996 Meydani19
Candies with antioxidants, fruit or vegetable extracts	Phytochemical antioxidant nutrients	Healthy hart Improves health in general	Indirect evidence	FDCA - claim on structure/function	ADA Report, 19996
Drinks with herbal additives	Variety: echinacea, kava, ginseng	Several benefits for health, anticarcinogenic properties, immune function	Epidemiologic/animal/human studies	FDCA - claim on structure/function	ADA Report, 19996 Sato & Miyata20
Grapes/grape juice	Resveratrol phenols	Healthy cardiovascular function	Epidemiologic studies	FDCA - claim on structure/function	ADA Report, 19996
Modified margarine	Phytosteroids, estanol ester	Healthy cholesterol levels	Clinical trials	FDCA - claim on structure/function	ADA Report, 19996 Thurnham, 199921 Vainio & Mutanen, 200022
Artichoke, banana, garlic, endive root, onion	Fructooligosaccharides Inulin (prebiotics)	Healthy intestinal microflora, immune function, reduces risk of developing diabetes type II, obesity, osteoporosis, cardiovascular diseases and cancer	Animal studies, clinical trials, evidence in humans	FDCA - claim on structure/function	ADA Report, 19996 Van Loo et al, 199923 Milner,199924 Roberfroid, 199925 Roberfroid, 200026
Soups with herbal additives	Echinacea	Improves immune function, reduces depression	Indirect evidence	FDCA - claim on structure/function	ADA Report, 19996
Soy	Soy protein (isoflavone - phytoestrogen)	Reduces risk of developing coronary disease, arteriosclerosis, breast cancer and osteoporosis	Clinical trials Animal studies Human studies	Health claim in process at FDA	ADA Report, 19996 Anthony et al., 199827 Karyadi & Lukito, 200028
Carrot	Carotene	Reduces risk of developing cancer	Epidemiologic studies	Health claim not submitted	ADA Report, 19996
Broccoli	Sulphoraphane	Reduces risk of developing cancer	Animal data, epidemiologic studies	Health claim not submitted	ADA Report, 19996
Green or black tea	Polyphenols	Reduces risk of developing coronary disease, gastric, esophageal and skin cancer Anti-inflammatory and immunostimulatory ability	Epidemiologic studies, clinical trials and animal studies	Health claim not submitted	ADA Report, 19996 Duloo et al., 199920 Sato & Miyata, 200029
Fish	Omega-3 fatty acids	Reduces risk of developing coronary disease	Epidemiologic studies (fish), clinical trials (omega-3 fatty acid)	Health claim not submitted	ADA Report, 19996 Connor, 199730 Gibson & Makrides, 200031
Beef, lamb and dairy products	Conjugated linoleic acid (omega-6)	Reduces risk of developing breast tumors	Animal studies	Health claim not submitted	ADA Report, 19996
Fermented dairy products	Probiotics (breast milk)	Reduces cholesterol levels and the risk of developing cancer, control of enteric pathogens	Epidemiologic studies, clinical trials, human studies	Health claim not submitted	ADA Report, 19996 Erickson & Hubbard, 200032 Lönnerdal, 200033 Roberfroid, 200025
Eggs with omega-3 fatty acids	Omega-3 fatty acids	Reduces cholesterol levels	Clinical trials	Health claim not submitted	ADA Report, 19996 Gibson & Makrides, 200031
Garlic	Organosulphur compounds	Reduces risk of developing cancer and coronary disease, control of hypertension	Epidemiologic/animal studies, clinical trials	Health claim not submitted	ADA Report, 19996
Medical food bar with arginine (formula)	L-arginine	Improves vascular health	Clinical trials	Medical food health claim	ADA Report, 19996
Medical food bar (formula)	Sucrose, protein, raw corn starch	Control of blood glucose during the night, prevents hypoglycemia	Clinical trials	Health claim not submitted	ADA Report, 19996

Adapted from ADA Reports, 1999, apud Torres, 2002³⁴.

An important fact to be emphasized is that these foods cannot be consumed in an exaggerated way. Since these products contain active substances in their composition, excessive consumption may cause harming effects if the intake goes beyond the recommended daily dose. This is important mainly if we consider all the vulnerable segments of society: although some data shown that the increased consumption of soy results in reduced risk of developing coronary disease and cancer, other studies have suggested some negative effects. The maximum amount of consumption of each food has still to be established.^24,35

Table 3 shows the level of ingestion of some functional foods in order to promote good health.

Table 3 - Approximate levels of ingestion for functional foods or compounds that promote extremely good health

Foods/Compounds	Level of ingestion	Association with diseases	References
Green or black tea	4-6 cups/day	Reduced risk of developing gastric and esophageal cancer	ADA Report, 19996
Soy protein	25 g/day 60 g/day	Reduced LDL levels, reduced menopausal symptoms	ADA Report, 19996
Garlic	600-900 mg/day (~1 fresh garlic clove/day)	Reduced blood pressure	ADA Report, 19996
Vegetables and fruits	5-9 servings/day	Reduced risk of developing cancer (colon, breast, prostate), reduced blood pressure	ADA Report, 19996
Fructooligosaccharides (prebiotics)	3-10 g/day	Reduced blood pressure, beneficial effects on the metabolism of lipids, improvement of gastrointestinal health, and reduced serum cholesterol levels	ADA Report, 19996
Fish rich in omega-3 fatty acids	> 180 g (6 oz)/week	Reduced risk of developing coronary disease	ADA Report, 19996
Grape juice or red wine	8-16 oz/day 8 oz/day	Reduced red cell aggregation	ADA Report, 19996
Vitamin E (antioxidant)	200 UI/day (supplement) + 5-8 servings of fruits and vegetables	Reduced risk of developing cardiovascular diseases, improvement of immune function	Meydani, 200019
Phytosteroids (sitosterol)	160-360 mg/day	Reduced hypercholesterolemia	Thurnham, 199921
Lutein and zeaxanthin (carotenoids)	2.3 mg/day	Reduced risk of macular degeneration with aging	Lajolo, 199836

Adapted from ADA Reports, 1999, apud Torres, 2002³⁴.

For angiologists and vascular surgeons, it is important to know what functional foods may be used in the prevention of vascular diseases. Efforts have been made in the sense of defining dietary recommendations for these diseases, since there is no doubt about the harming effects of animal fat and its derivatives on the etiology of cardiovascular diseases. Nowadays, a major marketing appeal is the development of foods that are rich in substances considered to be beneficial for the heart and arteries. This new view opposes to the restriction or prohibition of harming substances and their replacement with other lipid compounds that would act favorably in the prevention of diseases, decreasing blood pressure, endogen cholesterol and blood triglyceride levels.⁶

Our body is able to synthesize most of the saturated and unsaturated fatty acids, but not essential fatty acids. These are divided into two groups: the ω 3 family (linolenic acid) and the ω6 family (linoleic acid). ω3 fatty acids are abundantly found in certain plants and in fish oil, while ω6 fatty acids are found in vegetal oils. The first (ω3) present two very important derivatives: EPA or eicosapentanoic acid and DHA or docosahexanoic acid. EPA is extremely important in the prevention of cardiovascular diseases and hypertension; DHA is able to prevent heart diseases and reduce triglyceride levels, not to mention its role in the development of visual and brain development.^21,22,30,31

ω6 fatty acids are precursors of prostaglandins and leucotriens, which are very important in the regulation of the hormone metabolism that includes the synthesis of cholesterol; however, an excessive amount of ω6 in the form of linoleic acid may pose risks to health. One problem is that the concentration of ω3 interferes with that of ω6, and therefore it becomes important to balance the proportion of ω3 and ω6 fatty acids in the diet. Diets rich in fish may supply the needs of essential fatty acids. Therefore, in addition to the reduction of fat and total cholesterol, the current trend of the food industry is to try to add EPA and DHA in foods.²

The literature presents extensive data about the correlation between dietary habits and atherosclerotic diseases, but data on other vascular diseases are rare. Our main books in the area do not mention the subject, and therefore this is a chapter that is still open to research. Is there any functional food that might be used in the prevention of the varicose diseases? Can functional diseases be treated with the help of any foods? These are the questions that need to be answered in the near future.

Of course we may advise our patients about the use of iron-rich foods in the treatment of anemia, contributing for cicatrization or even improving blood flow in the limbs. The introduction of foods or dietary supplements enriched with vitamins C and A, pantothenic acid and zinc help heal wounds. There is no literature available about which foods might help in the maintenance of vein valves and walls, but the control of obesity by the angiologist and vascular surgeon is of paramount importance. Either in the case of referring the patient to a specialist or of the angiologist providing nutritional advice himself/herself, the concern regarding loss of weight by the patient is extremely important.

Another aspect that should be considered is related to the high cost of some novel foods, mainly if we consider that people would obtain the same results by eating more fruits and vegetables in their diet. The professional from the vascular area, therefore, has to keep in mind how important the concept of a balanced and healthy diet is. Functional foods are an irreversible commercial trend, but we should be alert not to induce incorrect dietary habits, replacing healthy and low-cost foods with novelties. A typical example is the replacement of breakfast with a cereal bar, or of milk with calcium-rich foods. The government has the role of supervising the food industry in the sense of guaranteeing that marketing campaigns will give priority to ethical and nutritional aspects and will not leave space for false interpretations by the consumers. Scientists, on the other hand, have the role of studying new substances to be used in the prevention of diseases and in the improvement of the global health of consumers.²

CONCLUSION

Healthy dietary habits are not related only to the type of food being ingested, but also to each person's lifestyle, genetic inheritance and environment. Therefore, there are not good or bad foods, but rather good or bad diets. Angiologists and vascular surgeons should be able to make this distinction so as to adequately advise their patients. Obesity control is fundamental both for the control of atherosclerotic diseases and varicose.

Functional foods, the object of the present work, should not be deemed as "magic" or considered as pharmaceuticals. Since this is a very recent field of investigation, a higher number of studies about the biologically active substances present in these foods is necessary to determine their beneficial effects more precisely and to quantify maximum and minimum doses that may be ingested by the population, so as to offer efficacy without posing toxicity risks and to assess side effects resulting from their used in the long term.

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