functional and modified foods

8/2/2019 Functional and Modified Foods

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Improved nutrition throughmodified and functional

foods

Contemporary Nutrition IssuesHSC Food Technology


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Previously we have looked at food nutrients (themacronutrients and micronutrients) which are essentialfor good health. These essential nutrients represent just

a fraction of the beneficial substances that are found infood.

Some of these beneficial substances are poorlyunderstood and still being researched; others have wellknown health benefits and have been used in marketing

new and modified food products, such as functionalfoods .

Functional foods are foods that have health benefitsbeyond those provided by the basic nutrients in thefood. These might be naturally occurring, or may be

added during manufacture. Nutritionally modified foods are foods that have

been altered in some way to improve their nutritionalcharacteristics, by adding or removing particularcomponents.


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There is a wide variety of nutritionally modified and

functional foods, and these can be grouped into threecategories;

1. Foods that naturally contain beneficial substancesother than the essential food nutrients. Suchsubstances include dietary fibre and phytochemicals

(beneficial plant chemicals found in fruits, vegetablesand other plant foods) such as anti-oxidants.

2. Foods with added active non-nutrients such asphytochemicals, modified starches, or probioticorganisms (beneficial bacteria normally found in a

healthy gut, that can improve health when consumedin food).

3. Other modified processed foods, where essentialnutrients (such as vitamins or minerals) have beenadded, or where something has been removed or

reduced (such as fat, sugar or salt).


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Active non-nutrient components offunctional foods

Active non-nutrients are substances that are notessential for life but which can enhance thefunctioning of the body or contribute to thepromotion of good health.

For example, fibre can help keep the gut healthyby providing fuel for beneficial bacteria, and bystimulating the muscle contractions (peristalsis)that keep the gut contents moving effectively.

Other active non-nutrients include phytochemicals,

which are beneficial substances found naturally inplants. Examples of phytochemicals include anti-oxidants and phyto-oestrogens.


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Anti-oxidants

There are at least 8000 differentanti-oxidants that occur naturallyin fruits, vegetables and otherplant sources.

The most significant anti-oxidantsare the nutrients vitamin E,vitamin C, beta-carotene and theother carotenoids (the precursorsof vitamin A), but there are manynon-nutrient anti-oxidants thathave significant benefits too.


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Flavonoids and carotenoids

Carotenoids and flavonoids are colour compounds foundin fruit and vegetables. They act as anti-oxidants and alsohave mild phyto-oestrogen effects.

Flavonoids can be divided into two subcategories:

anthocyanins, which contribute most of the red,

purple and blue colours of fruit and vegetables; anthoxanthins, which are pale yellow.

Carotenoids are the chemicals that contribute to yellow,orange and some red colours of fruit and vegetables. One ofthe most thoroughly researched carotenoids is lycopene, a

dark red carotenoid found particularly in tomatoes.Lycopene is thought to be protective particularly againstprostate and breast cancers.


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Antioxidants Of all the anti-oxidants, vitamin E seems to be most

involved in controlling blood cholesterol levels. Vitamin Eacts to stop low-density lipoproteins (LDLs) from breakingapart and depositing cholesterol along blood vessels.. Thereis also evidence to suggest that vitamin C assists vitamin E

in this anti-oxidant role. The anti-oxidants in fruit and vegetables may also help

reduce the risk of developing cancer of the prostate,bladder, oesophagus or stomach.

Experimental studies have indicated that taking anti-

oxidants in supplement form does not have the samebeneficial effect as eating them in food. This may be due tothe fact that the anti-oxidants work together in the body asa whole system, and foods provide multiple parts of thesystem in the right amounts, while supplements do not.


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Phyto-oestrogensPhyto-oestrogens are another category of phytochemicals.

They are substances that are converted, by bacteria in thegut, into hormone-like compounds which can imitate thehormone oestrogen . There is some evidence that thesechemicals have benefits including:

for women, a reduction of uncomfortable symptoms of

menopause (such as hot flushes) for both men and women,improved cardiovascular health (because the chemicals caninhibit the oxidation of the low-density lipoproteins)

most importantly, a reduction in the risk of cancers that arestimulated by the sex hormones (for example, breastcancer in women and prostate cancer in men).

The most significant sources of phyto-oestrogens are:

1. isoflavonoids , which are found in fruits, vegetables, seeds, nuts andlegumes. The most powerful source is the soya bean, which contains thestrongest oestrogen like substances, genistein and daidzein.

2. lignans , which are found in grains and seeds. The single richest source

of lignans is linseeds.


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Dietary fibre

Fibre is not considered a nutrient, but does help to keepyour gut working well, so it is still important as a beneficialsubstance found in food.

Fibre is found only in plant foods, and includes a variety ofgums, gels and indigestible carbohydrates that absorb

moisture in your gut, swelling to create a larger and softerfaecal mass. This makes the faeces easier to pass,stimulating the intestinal muscle contractions (calledperistalsis ) that keep your gut contents moving. Thismeans that the gut contents move through the body morequickly, reducing the time that any toxins are in contactwith gut cells. This may reduce cell damage and protectagainst some cancers.

Fibre also acts as a fuel for the beneficial bacteria in thegut, encouraging them to multiply. These then benefit thebody in return, protecting against infection and producing

substances that the body can use, such as vitamins-


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Fibre

Fibre is often classified into two categories, soluble fibreand insoluble fibre.

Soluble fibre is the type that dissolves into a gel in the gut,and is digested by bacteria in the colon. It helps increasethe feeling of fullness after eating, slowing the rate that the

stomach empties. It may also help to reduce cholesterollevels.

Insoluble fibre is the type often called roughage thatremains mostly unchanged while passing through the gut. Itis the main promoter of movement through the gut,protecting cells from damage.

Although these two types can be distinguished by theireffects, in reality most plant foods contain both types offibre.

Fruit, vegetables, nuts, seeds and legumes are all goodsources of fibre, but you can also obtain dietary fibre fromfibre supplements and from processed foods that have


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Omega-3 fatty acids

The name omega-3 refers to the chemical structure of thefatty acids, indicating they are unsaturated, with their firstdouble bond occurring at the third carbon on the chain.

Omega- 3 fatty acids can be converted to hormone-likesubstances called prostaglandins that are directly involved

with the correct functioning of the cardiovascular system. There are different types of prostaglandins, which have

many different roles in increasing or decreasing blood flow,muscle contractions, inflammation, and the immunesystem.

The prostaglandins that are associated with omega-3 fattyacids are anti-inflammatory, helping to reducecardiovascular disease by:

reducing the formation of clots in the bloodstream

protecting against serious heart rhythm disorders

helping to correct impaired blood vessel function.


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Omega-3 fatty acids are also important for normal braindevelopment in infants and children, and it has been

claimed that they have other benefits to do with brainfunction, such as relieving depression and reducingmemory loss associated with ageing.

Most of the evidence for benefits of omega-3 fatty acidsrelates specifically to DHA and EPA (docosahexaenoic

acid and eicosapentaenoic acid). Fish and fish oils are the best sources of omega-3 fatty

acids. Plant sources of omega-3 fatty acids providemainly ALA. These sources include canola oil, flaxseedoil, soya beans and linseed.

Omega-3 fatty acids are now added to a wide range ofprocessed foods including margarines and breads, andin Japan are even used in some chewing gum products.

The omega- 3 content of primary produce can beincreased if producers use stock feeds that are high in

omega-3 fatty acids. Omega- 3 enriched eggs are awidel available exam le.


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Probiotics The human gut contains billions of bacteria in fact, if your

gut is healthy, there may be more bacteria cells in yourbody than human cells!

Some bacteria are harmful and can cause illness, but ahealthy gut has a protective lining of good bacteria toshield you from these.

These beneficial gut flora also help maintain good health bymaking vitamins and contributing to the nutrition of the gutcells.

Probiotics are another name for these beneficial bacteria,when they are added to foods to promote health.

Gut infections or surgery, a poor diet, or particularmedications (such as antibiotics) can reduce the numbers ofhealthy gut flora, and probiotic foods are often used inthese situations to increase them again.

The health benefits of yoghurt have been known forhundreds of years, and many of these benefits are due to


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More recently, other bacteria strains have been used in foodproducts.

Although beneficial bacteria happily survive in the colon,they normally do not live in other parts of the gut. In fact,one of the functions of stomach acid is to kill bacteria eatenin food, and prevent them passing into your lower gut andcausing infection. This means that many of the normal gut

flora cannot be used as probiotics in food, as they would notsurvive the journey to the colon where they do theirbeneficial work. Researchers have been working to identifysuitable bacteria that can survive during the shelf-life of thefood product, and in the stomach acid, and during the

process of digestion in the small intestine, to reach thecolon safely.

Some different bacteria that you might see on food labelsinclude Lactobacillus acidophilus and Bifidobacteriumbifidum (used together in many different yoghurt products),Lactobacillus rhamnosus GG (used in Vaalia yoghurt), andLactobacillus casei Shirota strain (used in Yakult).

functional and modified foods

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