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Monday, August 8, 2011

Role of Salt in Hypertension


Hypertension or high blood pressure has become a common problem for the modern man. Modern lifestyle habits, nature of work, lack of exercise and poor dietary habits are some of the factors which are leading to hypertension in the present generation. A persistent high pressure increases the risk of a heart attack, stroke or congestive heart failure thus affecting the longevity of life. High blood pressure may even damage eyes and kidneys.

Hypertension or high blood pressure


Blood gets circulated throughout our body through arteries and veins. Our heart acts like a pumping machine which collects the deoxygenated blood and supplies the oxygenated blood to the body. The increase in blood pressure is noticed during two conditions, that is, during the increase in the volume of blood or when there is a constriction in the blood vessels. These two conditions lead to an elevation in the systemic arterial blood pressure.

How does the salt intake affect hypertension?


Table salt or sodium chloride is one of the main constituent of our diet. Apart from adding taste to our food it performs vital functions like water regulation in our body. It gets absorbed by our gastrointestinal tract and is excreted out by our kidneys. The excess of salt is flushed out by the kidneys to maintain the balance in our body. But if the salt intake is too high and if kidneys fail to cope up, the excess of salt gets accumulated in our bloodstream. Salt draws more water by the process of osmosis and leads to water retention in the blood vessels. This excess volume of blood creates pressure on the walls of the blood vessels leading to hypertension.

Dietary recommendations for the salt intake


We require 500 milligrams of salt every day for the normal functioning of the body. Our sodium intake should be kept between 2-3 grams.

Richness of sea salt


Research shows that hypertension is noted more in the cases of people consuming table salt which has 99.9 percent of pure sodium chloride. On the other hand sea salt which contains about 95 percent of sodium chloride, 4 percent of potassium chloride and the rest being a mixture of vital minerals like magnesium, iodine and trace elements has found to be a better option for hypertensive patients.

Sea salt is manufactured by the evaporation of sea water and usually exists in the form of crystals. The sea salt has a refreshing taste and is lightly flavored than the table salt.

Our body requires a perfect balance between the minerals like sodium and potassium. In fact a higher intake of sodium accompanied with a lower intake of potassium may lead hypertension. So the intake of sea salt is advisable for hypertensive patients.

Suggested measures to reduce salt intake


Salt intake has been directly associated with hypertension. Hence it is a common advice of all the doctors to reduce the salt intake. Slight modifications in our cooking practices help us to lead a better life. For example salt should be added during the process of cooking and not after the cooking is complete. Actually food should be cooked along with salt for at least 10 minutes.

Processed foods like chips, have a very high salt content. Salt is sprinkled over these items for better taste and this is harmful for our body. Even pickles and canned foods contain a higher content of salt. So it is advisable to avoid such processed foods.

Fresh fruits and vegetables are rich in nutrients and antioxidants. Eating these fruits and vegetables is good for our health.

Natural food items cooked in a lesser amount of sea salt are ideal for hypertensive patients.
 
Salts which when consumed in moderate quantities might control Bp. Buy on amazon

Natural Food Preservatives


Preserving food for long time was a necessity of mankind since time immemorial. The availability of certain food items was limited to a particular season. Man's desire to use them throughout the year motivated him to invent certain methods by which food items could be stored for a longer duration without a significant change in taste.

Food items can be categorized into perishable and non-perishable food items. Perishable items are those which get spoilt soon and are more prone to the attack of micro-organisms. Examples of some such items are vegetables, fruits, meat, eggs, milk etc. These items have a very short shelf life. On the other hand non-perishable foods are those which take a long duration to get spoilt like rice, wheat, oils, dried pulses etc.
The aim of using preservatives is to convert these perishable food items to non-perishable ones or extend the shelf-life. Food gets spoilt due to the attack of micro-organisms like bacteria, fungi, yeast etc. They bring some undesirable chemical changes in the food. Food preservatives inhibit these chemical changes through various ways.

Food preservatives are of two types: natural and artificial; and both try to maintain the quality, edibility and nutritive value of the foods.

Classification of Natural Food Preservatives

Depending on their mode of action, food preservatives are broadly classified into three kinds.
  • Antimicrobial preservatives which inhibit the growth of the microorganisms
  • Antioxidant preservatives which inhibit the oxidation of food ingredients like fats, lipids etc
  • Preservatives which target the enzymes within the food stuffs and hence prevent the natural activities like ripening of food or post harvest ageing of food stuffs.
Some of the natural food preservatives include substances like salt, sugar, rosemary extract, essential oils, vinegar etc. Out of these, substances like salt, sugar and oils are used in our day-to-day life. Ongoing research is targeted towards the search of some new natural food preservatives. Let us discuss about a few preservatives in detail.

Salt: Salt has been used to preserve food items like meat and fish since ages. At very high concentrations of salt, the cells of the micro-organisms loose water and dehydrate by the process of osmosis. It inhibits the growth of bacteria, yeasts and molds by the process of osmosis. Salting of meat preserves it for years. During pickling, raw mangoes, tomatoes etc are treated with considerably large amounts of salt. Even some vegetables like cabbage cauliflower and cucumber can be preserved by pickling them with salting.

Sugar: Sugar is a carbohydrate and the mechanism by which it stores food is same as that of salt. This substance also dehydrates the microorganisms by the process of osmosis. There are two ways in which the food stuffs can be stored in sugar.
  1. Thick concentrated sugar syrup can be prepared and the food substances can be immersed in it.
  2. The food items can be cooked in sugar until sugar reaches the point of crystallization. A higher concentration of sugar sweetens the food and either inhibits the growth of microorganisms or kills them by the process of osmosis. Sugar is generally used to preserve fruits like apple, peach, pear, plum etc in the form of jams and jellies.
Vinegar: This acidic solution is prepared by the fermentation of sugar and water solution. The process of fermentation is carried beyond the alcohol stage. Vinegar contains acetic acid which kills the bacteria due to its acidity or lower pH. Vinegar is used to preserve meats and vegetables during pickling. Even during the process of canning vinegar is used to increase the shelf life of the food items.

Rosemary Extract: This is prepared by the distillation of rosemary leaves and is known for its pleasant aroma and flavor. This substance has been used as a preservative since ages because of its antioxidant properties. It prevents the oxidation of food stuffs thus retaining the flavor and color of the food. The natural compounds present in the Rosemary extract like phenolic diterpenes, rosmarinic acid, carnosol are responsible for its antioxidant properties.

Some Traditional Practices of Food Preservation

With the advancement in technology, man has conquered many difficult situations. In olden days, means of transport were not that efficient and moreover crops and vegetables grown in a particular area were very much dependent on the seasonal conditions in that area. These conditions encouraged people at that time to adapt certain practices which helped them to preserve food throughout the year. Some of these traditional practices are as follows -
  • Indian plums, commonly known as ber in Hindi and regu pandu in Telugu, is a seasonal fruit which is generally seen in the market between January and March. A dish called regu adaa helps to preserve it for the whole year. To prepare this, seeds are removed and the fruits are beaten into a semi-solid paste. After adding salt, the paste is made into small biscuits and then sun dried.
  • Cluster beans, commonly known as Guar-ki-phalli in Hindi and goru chikkudu in Telugu, is a nutritious vegetable. In order to preserve it, it is cut into medium size pieces, about one to one-and-a-half inch in length and soaked in buttermilk along with salt. This has to be soaked for a span of 24 hours and then sundried. These sundried pieces can be fried in oil and eaten along with rice.
  • Coccinia cordifolia, commonly known as kundru in Hindi and dondakayi in Telugu, can be cut into pieces.  After applying salt to these pieces, they can be sun-dried and later these pieces can be stored for a long duration. Whenever required they can be fried and taken along with rice.
  • Brinjal, commonly known as baingan in Hindi and vankai in Telugu, is a very commonly used vegetable across India. Even this vegetable can be cut into pieces and dried in sun after applying salt. Before cooking, the dried pieces have to be soaked for half-an-hour in water and then can be used to prepare a tasty curry along with tamarind water and jaggery.
  • Mango - Good raw mangoes are available only in the summer season. They can be preserved in different forms of pickles. Apart from that small mango pieces can be sundried after application of salt. These mango pieces can be added to dhal through out the year.
It is true that nowadays we get all the food stuffs throughout the year with a variation in price. Fruits are no longer seasonal and they are ripened with the help of chemicals like ethylene. A few months back around November 2010 there was a heavy increase in the market price of all the vegetables. This crisis situation stayed for a span of three months but it affected many people. If we can adopt these traditional practices in our day to day life we can be ready to face any sort of odd situations. Not only this, we can prevent the wastage of huge quantities of food items also.

Acknowledgements:
  • The information in this article is primarily sourced from discussions on preservation techniques with the author's mother-in-law, Mrs. Haimavathi, who has used the techniques in the past and still continues to follow some of these practices.

Pollinator Shortage Affects the Global Health

Pollinators play a central role in the reproductive propagation of flowering plants. Tiny insects or animals which act as pollinators include honey bees, butterflies, hummingbirds, bats, and ants. Plants yielding nutritionally rich fruits and vegetables are dependent to a large extent on pollinators.

Since past 50 years production of staple crops like rice, potato, wheat, yam etc has almost doubled. These crops mainly supply energy to our body and they are mostly wind-pollinated, self-pollinated, or vegetatively propagated. However our diet is incomplete without certain vital nutrients like vitamins and minerals and they are supplied by animal or insect pollinated plants.

According to the recent research conducted by Eilers et al. (2011) majority of oil produced from the plant sources comes from the plants which are animal pollinated. Vital nutrients like vitamin A, C and E come from animal pollinated fruits and vegetables. It has been estimated that approximately 70% of vitamin A and 98% of key nutrients like
Carotenoids, lycopene and ß-cryptoxanthin are obtained from plants which yield red, orange and yellow vegetables and fruits. These nutrients help us to fight cardiovascular diseases and cancer and are a source of antioxidants to the body. Plants like beans and dark green leafy vegetables are rich in folic acid which is very essential during pregnancy.

Eilers and his team have noticed a direct correlation between the increases in the yield of these plants with the increase in the number of pollinators. Apart from this the supply of certain vital minerals like calcium and fluorine and iron, increases with an increase in pollination of plants like beans, almonds and nuts.

Human intervention has reduced the number of pollinators to a very large extent. Deforestation over a vast area destroys the habitat and depletes the source of food for pollinators. This automatically reduces their number. Monoculture-based agricultural production that is planting similar crop year after year with a support of chemicals in the form of fertilizers and pesticides not only depletes the soil of its natural fertility but also reduces the number of pollinators. Some other factors which effect the pollinator population include, pesticides, insect and animal diseases and parasites.

A large number of nutrient supplements are available in market. But are they affordable to a common man belonging to the developing country? Moreover the synthesis of these supplements involves huge expenditure. Should we go ahead with the rampant use of chemicals to increase the food production or revert back to traditional eco-friendly farming practices? The choice is left to us.

References

Eilers EJ, Kremen C et al. Contribution of pollinator-mediated crops to nutrients in the human food supply. PLoS One. 2011;6(6):e21363

Manipulation of Plant’s Defense by Herbivores Poses Challenge to Entomologists


Plants have inherent defensive mechanism which protects them from their predators and phytopathogens. Their inability to move is largely complemented by the defensive adaptations which help the plants to survive and reproduce successfully. One of the most important defensive mechanisms is production of secondary metabolites. These metabolites are the chemical substances which are not involved in the normal photosynthetic process of the plants. They are alternatively known as allelochemicals and they can influence the behavior, growth, or survival of herbivores. Allelochemicals act as toxins to herbivores and in some cases also reduce the digestibility of plant cell wall.

Some external structural features on the stem and the leaves (prickles, spines, thorns etc) discourage herbivory to a very large extent. These mechanical defensive mechanisms deter, injure, or kill the grazer. Some defensive substances like wax, resins, lignins, etc. are released on the plants’ epidermis and prevent the herbivores from feeding on them. Apart from these, sensitivity to touch shown by Mimosa pudica is another example of defense mechanism in plants.

Herbivores form a primary link in the food chain, as they are the source of energy for organisms ranking higher in the food chain. Plants are the only source of food for herbivores and this led to the co-evolution of adaptations, which help them to acquire their food, irrespective of the defense mechanisms in plants. Some of these adaptations are:
·        synthesis of enzymes which can reduce the effect of secondary metabolites
·        existence of internal symbiotic bacteria, fungi, or protozoa which help to break down the plant cellulose so that it can be digested by the herbivore
·        mechanical adaptations like incisors in moths which helps them to eat soft leaves.

Amongst these adaptations, host manipulation is the most important mechanism by which herbivores feed on the plants in a better way. According to the recent research conducted by Renato Almeida Sarmento and his team, invasive spider mite Tetranychus evansi, manipulates its host (tomato), by interfering with signalling pathways involved in its defense mechanism [1].

Primary hosts for T. evansi are solanaceous crops like tomato, potato, tobacco etc. These mites puncture the leaves while feeding, leading to yellowing or whitening of leaves. Subsequently the leaves fall down and in case of severe attack the plant dies. The study conducted by Sarmento, suggests that T. evansi, manipulates the host defense mechanism by suppressing the induction of the salicylic acid and jasmonic acid signalling routes which are involved in plant defenses in tomato plant [1]. Salicylic acid and jasmonic acid play a vital role in plants immunity. Spider mites reduce the levels of inducible defense compounds and volatiles (example, proteinase inhibitors) which play a crucial role in plants defense.


Crops like tomato and potato find a widespread use across the world. Control of pathogens affecting these crops is a vital area of research. The result of the research by Sarmento, provides a better understanding of the plant–herbivore interactions. It opens the gateway for further research in two directions:
·        Biological control of Tetranychus evansi at an affordable cost to the farmer.
·        Developing crop varieties which are able to combat the manipulations by herbivores.

Reference:

Sarmento R, Lemos F et al. A herbivore that manipulates plant defense. Ecol Lett. 2011 March 14(3): 229–236.


Organ Donation – Saves another Life


During organ donation, solid organs like kidney, heart, pancreas, liver, bone marrow, eyes and limbs, are removed from the body of the donor and transplanted into the body of the recipient. Some of these organs can be preserved and utilized for future transplant. Vital organ like heart cannot be removed from a living person. Hence such organs are acquired from cadaver donors, who have died recently. Organs are separated from live donors in two cases

1)     When the organs are present in pairs. Example kidney
2)     When the removal of a portion of an organ does not effect the functioning of organ. Example liver, bone-marrow, pancreas

Legalization of transplantation of human organs has given rise to the concept of brain dead. Brain death is state of legal death. In this state the heart continues to beat and all the vital organs are kept alive and functional with the help of mechanical ventilation. This is a state during which the brain is dead and in an unrecoverable state – meaning – cannot be brought back to life. This condition is optimum to remove the organs for transplantation.


Consent of the Donors

Organ donation should happen only with the consent of the donor, if alive.  In most cases, the donor registers himself or herself as a donor where he agrees to donate specific organs on his death.  This is very common in the case of eye-donation and there are multiple organizations catering to this. After getting registered, the donors are issued a card which certifies their wish to donate organs. It is the donor’s responsibility to keep his family informed of his decision so that in case of death, the family can notify the organization that registered him.  The organizations try to reach the person in the earliest possible time to retrieve the organs after death. In some cases, the family of a victim of an accident may decide to donate the organs of the brain-dead victim. 

National Marrow Donor Program maintains a list of people willing to donate bone marrow to a stranger and here are some links given below where we can register ourselves as organ donors



Regulation of Organ Donation

Organ donation and transplant has always had a lot of regulation surrounding it. 
The reasons behind intense regulation are many, primary reason being exploitation and corruption. Seeing the high demand of organs, doctors and organ vendors try to exploit a common man by taking out his organs without his consent. Organ selling is legally banned in India but there are many areas where poor people are encouraged to sell their organs in return of money. On the ethical side, questions like - can a person who is mentally retarded be allowed to donate, can infants be donors, and so on have necessitated the stringent regulation of organ donation.

Does organ transplantation bring an end to the treatment procedure?

Once an organ is implanted into the body a long journey of recovery with intense medication begins. The body recognizes an implanted organ as a foreign body and the immune system wakes up. It tries to produce antibodies against the implanted organ and hence rejecting it. The patient is kept on strong immunosuppressant drugs for a long duration to allow the implanted organ to work properly.

Milestones Covered on the Road of Organ Transplant

  • Transplantation of kidney was only feasible in the beginning but now transplantation of heart, liver, pancreas, skin, bone marrow, limbs intestines etc is also feasible.
  • Now we have a wider choice as we can collect organs from both living and dead people.
  • Discovery of strong immunosuppressant drugs has increased the success rate of organ transplants.
  • Xenotransplantation or use of animal organs for human transplantation has takes us a step ahead. Example Chimpanzee kidneys were transplanted into patients with renal failure. A baboon heart was transplanted into a newborn infant.
  • Syntheses of artificial organs for transplantation – Examples in this line are bionic eyes and ears, artificial heart.
  • Organ from a single donor is being used for more than one patient by splitting it. Example split liver transplant where liver from a single donor was used for implantation into multiple recipients.
  • Pioneering research – Stem cells have an enormous capacity to develop into any kind of tissue within the body including organs. Scientists aim to synthesize organs using the stem cells.


A large number of deaths have been reported to be due to the lack of organs ready for transplantation. Many patients live years together on expensive dialysis as they do not get a kidney donor. Lack of public awareness and inclination towards organ donation are main hurdles in this line. Galore of controversies and ethical issues surrounding organ donation accompanied by unawareness have made this procedure difficult. A voluntary organ donation saves another life.

Preservation of Suji or Semolina


Suji is vital ingredient in many Indian foods like upma, halwa, vada, laddoos, rava dosas etc. A porridge made of suji is a good weaning food for toddlers. Suji rava is prepared from wheat. The wheat grains are fed into rollers to remove the bran and germ. The remaining starchy part or the endosperm is broken down into pieces. A sieve made of net or mesh is used to separate the lighter part which is bran. The semolina pieces are further crushed to obtain fine flour.

Suji is a high calorie diet which provides energy for long period after consumption. It provides complex carbohydrates to our body. It is a processed food and vital components of grains like bran (fiber rich part) and germ (rich source of vitamin B complex, vitamin E, and minerals like Iron and calcium and magnesium) are lost during processing.

However nutritional value of any food item depends a lot on the method of preparation also. Many dishes like suji roti, rava-ragi rotis, rava idlis, rava dosas etc can be prepared using very less amount of oil. This will reduce the fat intake and also reduce the cholesterol levels. We can also add some grated vegetables in these dishes to supplement other nutritional requirements. We can prepare a wide variety of yummy dishes by slightly changing the formula of cooking. Isn’t that great about suji!

Porridge of suji with milk and sugar is cherished by infants. This gets easily digested and can be supplemented with smashed vegetables and fruits for a wholesome diet. Suji is generally stored in containers on the shelf and does not require refrigeration. Rava can be considered to be good until the rava granules are separate like that of sugar. However upon infestation, it starts forming threads. We can increase the shelf life of suji. All we need to do is fry siji for a few minutes over a low flame. After frying for few minutes the colour of rava turns out to be light brown accompanied with nice aroma. This should be cooled properly and then packed in air tight containers. This technique extends the shelf life of suji. Even after this if we find any signs of infestation it should be sun dried and used as soon as possible.

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