Nutrition and Immunity

Ranjit Kumar Chandra wrote . . . . . . . . .

Introduction

It is now generally accepted that nutrition is an important determinant of immune responses. Epidemiologic and clinical data suggest that nutritional deficiencies alter immunocompetence and increase the risk of infection. Poor sanitation and personal hygiene. overcrowding. contaminated food and water, and inadequate nutrition knowledge contribute to this susceptibility. Work done in the past 25 y has confirmed that impaired immunity is a critical adjunct factor in malnutrition-associated infection. This concept applies not only to young children in developing countries but also to all age groups in all populations of the world. including the elderly, those with eating disorders, and patients with a variety of primary debilitating diseases. A list of reviews and monographs is provided for further reading and citations to specific findings.

The Immune System

Detailed descriptions of the immune system and its dysfunction in primary and secondary immunodeficiency disorders can be found elsewhere. Host resistance mechanisms can be divided into two main tiers: nonspecific and antigen specific. The nonspecific defenses include the skin and mucous membranes, phagocytic cells, mucus, cilia, complement, lysozyme, interferon, and other humoral factors.

These innate processes are naturally present and are not influenced by prior contact with the infectious agent. They act as the first line of protection and retard the establishment of overt infection. Antigen-specific mechanisms include the B cell system of antibody production and the T cell system of cellmediated immunity. These mechanisms are adaptive and ac- quired in that they are specific reactions induced by prior exposure to the microorganism on its antigenic determinants.

They are effective in checking the spread of infection and eradicating the invading organism. The specific immune re- sponses form the basis of prophylactic immunization against common communicable diseases such as measles, respiratory illness caused by Hemophilus influenza, and systemic disease caused by Salmonella. In the body, nonspecific and antigenspecific defenses act in concert.

Protein-energy Malnutrition

Lymphoid atrophy is a dramatic feature of protein-energy malnutrition (PEM). The size and weight of the thymus are reduced. Histologically, there is a loss of corticomedullary differentiation; there are fewer lymphoid cells; and the Hassall bodies are enlarged, degenerated, and occasionally calcified. These changes are easily differentiated from findings in primany immunity deficiency, such as DiGeorge syndrome.

In PEM there is also a loss of lymphoid cells around small blood vessels in the spleen and in lymph nodes the thymusdependent paracortical areas show depletion of lymphocytes.

In PEM most host-defense mechanisms are impaired. Delayed-hypersensitivity cutaneous responses both to recall and new antigens are markedly depressed. It is not uncommon to have complete anergy to a battery of different antigens. These changes are observed in moderate deficiencies as well. The skin reactions are restored after appropriate nutritional therapy for several weeks or months. There is also a reduction in mature, fully differentiated T lymphocytes due in part to a reduction in serum thymic factor activity. Additionally, deoxynucleotidyl transferase activity in leukocytes is increased.

The proportion of helper inducer T lymphocytes recognized by the presence of CD4+ antigen on the cell surface is markedly decreased. There is also a moderate reduction in the number of suppressor cytotoxic CD8+ cells. Thus, the ratio of CD4+ to CD8+ cells is significantly lower than that in well- nourished control subjects. Moreover, co-culture experiments showed a reduction in the tiumber of antibody-producing cells and in the amount of immunoglobulin secreted. This may largely be due to decreased help provided by T lymphocytes. Lymphocyte proliferation and DNA synthesis are shown to be reduced, especially when the autologous plasma from a patient is used in cell cultures. This may he the result of inhibitory factors as well as deficiency of essential nutrients in the patient’s plasma.

Serum antibody responses are generally intact in PEM, particularly when antigens in adjuvant are administered or for materials that do not evoke T cell response. Antibody affinity, may provide an explanation for a higher frequency of antigenantibody complexes found in such patients. Secretory immunoglohulin A (sIgA) antibody concentrations are lower after immunization with viral vaccines; there is a selective reduction in sIgA concentrations with some compensatory increase in IgM concentrations in secretions. This may have several clinical implications, including an increased frequency of septicemia commonly observed in undernourished children.

Phagocytosis is also affected in PEM. Complement is an essential opsonin and the concentrations and activity of most complement components are decreased. The best documented is a reduction in C3, CS, factor B, and total hemolytic activity.

There is a slight reduction in opsonic activity of plasma. Furthermore, metabolic activation and intracellular destruction of bacteria are reduced. Finally. recent work in humans and animals showed that the production of several cytokines, including ititerleukins 1 and 2 and interferon y. is decreased in PEM. Moreover, malnutrition alters the ability of T lymphocytes to respond appropriately to cytokines. There is little work on the effect of malnutrition on the integrity of physical barriers, quality of mucus, or several other innate immune defenses. For example, lysozynie concentrations are decreased, largely as the result of reduced production by monocytes and neutrophils and increased excretion in urine. Adherence of bacteria to epithelial cells is an essential first step before invasion and infection can occur. The number of bacteria adhering to respiratory epithelial cells is increased in PEM.

Micronutrients

Several trace elements and vitamins have an essential role in key metabolic pathways and immune cell functions. Isolated deficiencies of micronutrients are rare with the exception of iron, vitamin A, and zinc. However, they frequently complicate PEM and iiiany systemic diseases. Moreover, human malnutrition is usually a composite syndrome of multiple nutrient deficiencies.

Observations in laboratory animals deprived of one dietary dcnient and findings in the rare patient with a single nutrient deficiency have confirnied the crucial role of several vitamins and trace elements in immunocompetence. Detailed description of the effect of micronutrients on immune responses is given elsewhere.

Five general concepts have been advanced. First, alterations in immune responses occur early in the course of reduction in micronutrient intake. Second, the extent of immunologic impairment depends on the type of nutrient involved, its interactions with other essential nutrients, the severity of deficiency, the presence of concomitant infection, and the age of the subject. Third, immunologic abnormalities predict outcome, particularly the risk of infection and mortality. Fourth, for many micronutrients excessive intake is associated with impaired immune responses and, finally, tests of immunocompetence are useful in titration of physiologic needs and in assessment of safe lower and upper limits of micronutrient intake.

Zinc is chosen as an example to illustrate these concepts. Zinc deficiency, both acquired and inherited, is associated with lymphoid atrophy, decreased delayed-hypersensitivity cutaneous responses, delayed homograft rejection, and lower thymic hormone activity. Patients with acrodermatitis enteropathica have impaired lymphocyte response to phytohemagglutinin, decreased thymulin activity, and reduced delayed-hypersensitivity cutaneous reactions. In laboratory animal models these findings can be confirnied and, in addition, one can show a reduced number of antibody-forming cells in the spleen and impaired activity of T killer cells, decreased ingestion, and reduced phagocytosis. Zinc is probably involved in stimulation of NADPH oxidase through its role as a cofactor for phospholipase A2 or phospholipase C. Zinc may stabilize arachidonic acid against oxidation by iron complexes. Zinc complexes may react with oxygen, generating products highly toxic to ingested pathogens. Wound healing is impaired in zinc deficiency. Zinc deficiency increases morbidity and mortality of animals challenged wtth various organisms, including Enterovirus coxsackie B and Lisieria monocytogenes. Zinc deficiency promotes the establishment of nematodes and alters the characteristics of their expulsion from the intestine although spontaneous cure is unaffected.

Important work needs to he done on the molecular basis of impaired lymphocyte and phagocyte functions in zinc deficiency. A slight excess intake of certain nutrients such as zinc may he associated with enhanced immune responses. It is known now that almost all nutrients given in quantities beyond a certain threshold will reduce immune responses. This has been shown for zinc for both phagocyte and lymphocyte functions. The mechanisms of these immunotoxic effects are not clear, but for zinc overdose, alterations in serum and cell-bound low-density lipoproteins reduced concentrations of other nutrients; changes in membrane structure and receptor expression are some possibilities.

The Elderly

There is much recent interest in and work on the effects of dietary intake and nutritional status on immunity and risk of illness in old age. The pattern of illness observed in the elderly suggests that immune responses decline in old age. Because of the close contact of the immune system with other systems in the body, any changes in immunocompetence can be expected to influence other organ functions as well. As immunologic vigor declines, incidences of infections, cancer, immune complex disease, autoimmune disorders, and amyloidosis increase.

Cellular and molecular manipulation including nutritional support to prevent or slow the decline of immune functions can be expected to delay the onset or decrease the severity of pathology associated with aging.

Age-related changes in immune responses have been the focus of much recent work. The number of plunipotent cells with the ability to colonize peripheral lymphoid sites and to mature into competent cells decreases with age. The ability of stem cells to undergo clonal proliferation decreases and the generation of B cells and homing of precursor cells into the thymus is reduced. This restraint on stem cell kinetics and reserves may be critical to an effective response to stress, such as infection.

Elderly patients with sepsis often fail to mount leukocytosis, although the expected shift to the left of immature polymorphonuclear leukocytes does occur. In the elderly, delayed-hypersensitivity cutaneous responses to ubiquitous recall antigens derived from bacterial and fungal products, as well as to 2,4-dinitrochlorobenzene, are reduced in frequency and in size. Lymphopenia and anergy have important prognostic significance in old age. The number of circulating T lymphocytes is slightly decreased. The number of CD4+ cells is decreased, whereas the number of CDS+ cells is variously reported as normal, decreased, or increased. Functional alterations associated with these changes in the number of cells include decreased lymphocyte proliferation in response to mitogens and antigens, reduced production of macrophage migration inhibition factor and of interleukin 2, impaired mixed lymphocyte reaction, and decreased natural killer cell activity. There is also a sharp decline in thymulin activity.

There is a reduction in serum IgG concentration and an increase in serum IgA. Generally, primary antibody response is decreased but antibody titer after booster immunization is often comparable in the young and the elderly. There is, however, a delay in reaching the peak antibody response in the elderly.

For many antigens, antibody production by B cells requires helper factors generated by T cells. Antibody responses to such antigens are decreased in old age and the affinity of the antibody may be reduced. There are no data on sIgA antibody responses of old individuals. Polymorphonuclear leukocytes obtained from the elderly have reduced migration ability, both random and chemotactic. The uptake of microorganisms is slightly reduced and has been attributed to a more rigid cell membrane. There is partial reduction in the magnitude of the metabolic burst associated with phagocytosis, and lysis of Candida is impaired.

Nutritional deficiencies are seen in at least one-third of the elderly in industrialized countries. Certain old individuals are at particularly high risk of malnutrition: the physically isolated; those living alone, especially those who have been recently bereaved; the socially isolated; those with sensory on mental impairment; those with a chronic systemic disease; the very poor; and the very old. Furthermore, a reduction in total energy intake results in inadequate consumption of certain essential nutrients. This is further compounded by a lack of variety and characteristic self-selection of food items, the presence of malabsorption in some elderly individuals, and drug-nutrient interactions.

The simultaneous assessment of nutritional status and immune responses and subsequent correlation analysis have suggested that impaired immunity in the elderly may be due in part to associated nutritional deficiencies. Several recent studies attempted to correct nutritional deficiencies in the elderly and examined the effects of such interventions on immune responses. In general, providing extra energy or multiple micronutnients or moderately large doses of single nutrients resulted in improved immune responses. In a few studies, this was associated with reduced infection-related illness. Much more work needs to be done in this area of considerable public health significance.

Concluding Remarks

The well-established effect of nutrition on immunity has led to several practical applications. These include the use of immunologic tests as prognostic indexes in patients undergoing surgery and the use of immunologic methods to assess nutnitional status and to judge the adequacy of nutritional therapy and improved immunologic response to and protective efficacy of vaccines. Finally, this new knowledge has permitted the development of designer feeding formulas with selective ingredients in specified amounts: these feeding formulas have been shown to reduce the risk of infection in animal models and in immunocompromised hosts. Clearly, the work on nutrition and immunity reviewed here has had a significant and crucial influence on public health and clinical medicine.

Source: Watermark

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What Are the Benefits of Eating Brazil Nuts?

Jamie Eske wrote . . . . . . . . .

Brazil nuts come from the South American Bertholletia excelsa, or Brazil nut, tree. They are a good source of healthful fats, protein, fiber, and selenium.

Despite its name, the Brazil nut is technically a seed rather than a nut. By definition, nuts are hard-shelled fruits that contain a single, large seed. Walnuts and pistachios are good examples.

Brazil nuts may offer surprising and powerful nutritional benefits, including boosting heart health, providing antioxidants, and improving brain function.

In this article, we discuss the health benefits of Brazil nuts, their risks, and how to add them to the diet.

1. Nutrition

Brazil nuts are among the richest dietary sources of selenium, an essential mineral with antioxidant properties. Selenium plays an important role in reproduction, metabolism, and immune health.

A single Brazil nut contains 68 to 91 micrograms (mcg) of selenium, meaning that just one nut per day can provide the daily recommended adult allowance of 55 mcg.

In addition to selenium, Brazil nuts contain plenty of protein, essential minerals, and healthful fats.

According to the United States Department of Agriculture (USDA), a serving of three Brazil nuts contains the following nutrients:

  • 99 calories
  • 2.15 g of protein
  • 10.06 g of fat
  • 1.76 g of carbohydrate
  • 1.10 g of fiber
  • 109 mg of phosphorus
  • 99 mg of potassium
  • 56 mg of magnesium
  • 24 mg of calcium
  • 0.61 mg of zinc
  • 0.36 g of iron
  • 0 mg of sodium

Given their impressive nutritional profile, it is no surprise that Brazil nuts have become so popular.

2. Heart health

Brazil nuts contain healthful fats called polyunsaturated and monounsaturated fatty acids.

According to the American Heart Association (AHA), consuming monounsaturated fats and polyunsaturated fats instead of saturated and trans fats helps improve cholesterol levels, which lowers the risk of heart disease and stroke.

Brazil nuts also provide dietary fiber. The AHA report that eating fiber-rich foods improves blood cholesterol levels and lowers the risk of heart disease, stroke, obesity, and type 2 diabetes.

The findings of a 2019 study showed that higher consumption of tree nuts decreased the risk of cardiovascular disease and heart attack among people living with diabetes.

3. Thyroid health

Selenium deficiency can cause hormonal imbalances that can negatively affect sleep, mood, concentration, and metabolism.

Selenium plays an essential role in hormone production. The thyroid gland uses selenium to convert thyroxine hormone (T4) into its active form, triiodothyronine hormone (T3).

Obtaining enough selenium from dietary sources may prevent or help regulate thyroid problems, such as hypothyroidism.

4. Antioxidant effects

The selenium in Brazil nuts may boost the body’s antioxidant system and prevent oxidative stress.

The liver breaks selenium down into a type of protein called selenoprotein P, which effectively removes excess free radicals. Free radicals cause oxidative stress, and research has linked them to many chronic health conditions, including cancer.

A double-blind, placebo-controlled study examined the antioxidant effects of Brazil nut consumption. During the study, 91 people with hypertension and high blood-lipid concentrations received either 13 g of granulated, partially defatted Brazil nuts or a placebo every day for 12 weeks.

The participants in the Brazil nut group had higher selenium levels and increased activity of an antioxidant enzyme called GPx3. They also had lower levels of oxidized low-density lipoprotein (LDL), which people sometimes refer to as “bad cholesterol.”

5. Anti-inflammatory effects

The antioxidant properties of Brazil nuts may help reduce inflammation in the body. Inflammation has an association with many chronic health conditions.

A small-scale 2014 study looked at the health effects of eating one Brazil nut per day in people with chronic kidney disease. After 3 months, the researchers noticed a reduction in inflammation and markers of oxidative stress.

6. Lowering blood sugar

Foods rich in selenium may help improve people’s blood sugar levels.

A study in the European Journal of Nutrition reported that eating one Brazil nut per day for 8 weeks lowered total cholesterol and fasting glucose levels in healthy adults.

The findings of another 8-week-long study showed that taking a 200-mcg selenium supplement reduced insulin levels and improved insulin sensitivity in people with type 2 diabetes and coronary heart disease. The researchers also reported increased antioxidant capacity in the body.

7. Improving brain functioning

Antioxidants help keep the brain healthy. Brazil nuts have powerful antioxidant effects, which may boost brain functioning.

Scientists have linked decreases in antioxidant function to cognitive impairment and neurodegenerative diseases, including Alzheimer’s disease.

The findings of a 2014 study suggested that people with Alzheimer’s disease have lower selenium levels than those without the condition.

A small-scale trial reported that eating one Brazil nut per day for 6 months had positive effects on some cognitive functions among older adults with minor cognitive impairment (MCI) compared with those in a control group. This result may be due to the nuts reversing selenium deficiency.

However, a recent study found no association between selenium levels and cognitive ability. More research is necessary to uncover how selenium affects cognition and to determine whether or not it could prevent or treat neurogenerative diseases.

Can you eat too many Brazil nuts?

When it comes to Brazil nuts, more is not necessarily better. People should limit their intake of Brazil nuts to a few per day to avoid negative side effects. Brazil nuts are high in calories, and eating too many can cause selenium toxicity.

Like most nuts, Brazil nuts are very calorie-dense. People who eat too many Brazil nuts run the risk of exceeding their daily recommended calorie intake. Consuming too many calories can cause unwanted weight gain.

As a member of the tree nut family, Brazil nuts may cause allergic reactions in some people. According to the American College of Allergy, Asthma & Immunology, an estimated 25 to 40 percent of people who have a peanut allergy react to at least one type of tree nut.

Selenium toxicity

Many of the health benefits of Brazil nuts come from their high selenium content. Although beneficial in small quantities, Brazil nuts could cause selenium toxicity if a person regularly eats them in large numbers.

According to the National Institutes of Health (NIH), selenium toxicity can cause a variety of symptoms, such as:

  • dizziness
  • gastrointestinal problems
  • hair loss
  • brittle nails
  • skin rashes or lesions
  • nervous system problems
  • fatigue
  • irritability
  • muscle tenderness or soreness
  • joint pain

It can sometimes also cause severe symptoms, which may include:

  • acute respiratory distress syndrome
  • heart attack
  • kidney failure
  • heart failure

In rare cases, selenium toxicity can be fatal.

The selenium concentration in Brazil nuts varies depending on the amount present in the soil so each nut may contain a different amount.

Source: Medical News Today

Is Grass-Fed Beef Better For You?

Monica Reinagel wrote . . . . . . . . .

When you see meat that’s labeled “grass-fed,” it means that after these animals are weaned, they eat only grass—and whatever other green stuff they might find growing where they graze—for the rest of their lives. During the winter, when nothing much is growing in the pasture, the animals can be confined in pens and fed dried grass (hay). But during the green season, they have to be allowed to roam around freely and graze..

Is Grass-Fed Beef Better for You?

What’s the alternative? Well, virtually all cattle start out eating grass. But when they’re 6 to 12 months old, most of the cattle that are raised in the U.S. are eventually sent to feed-lots, where they eat corn and other grains for the balance of their lives. It turns out that feeding cows grain instead of grass fattens them up quickly. (The same seems to be true of people!) The end result—in the case of the cows, that is—is meat with a higher fat content, and animals that are ready for slaughter sooner.

Ironically, the term “corn-fed” used to be a good thing—signifying well-marbled, flavorful beef. How times have changed!

Is Grain Unhealthy for Cows?

Critics point out that grain is not a natural diet for cud-chewers like cows and that feeding corn to cows causes digestive problems and generally makes them sickly. (Even though humans are not cud chewers and have completely different digestive systems, there are those that argue that a grain-based diet makes us sickly as well.) Most grain-fed cattle get antibiotics mixed into the feed to help keep them healthier—which has definite downsides. (See my article, Antibiotics in Meat.)

If you’re fattening your cows on corn, you also can keep them in a feed lot where you simply fill up tubs with the grain. This allows farmers to keep lots and lots of cows in a relatively small amount of space. For grass-fed cows, you need, well, grass—and lots of it. Instead of standing around in crowded feedlots, grass-fed cows get to be out there where the antelopes roam for at least part of the year. Even though the cows have to work a little harder for their supper, a lot of people feel that the pasture lifestyle is a whole lot nicer and healthier for the cow.

Is Grass-Fed Beef Any Safer?

One of the ways that we humans defend ourselves against food-borne pathogens like E. coli is by bathing our food in stomach acid, which kills most of the bacteria. Advocates of grass-fed beef claim that a grain-based diet acidifies the digestive tract of the cows, which encourages the growth of E. coli that are more tolerant of acidic environments and, therefore, more dangerous to humans.

However, this widely-believed theory has not borne up well under scrutiny. Analysis of beef products in the marketplace consistently finds the same rates of bacterial contamination in the grass-fed meat as in the grain-fed meat—including the most dangerous strains. I’m afraid that until they invent a cow that doesn’t poop, E. coli will always be a threat.

Is Grass-Fed Beef Organic?

Grass-fed is also not synonymous with organic: Organic cows may be fed grass or grain and grass-fed herds are not necessarily raised according to organic standards. Certified organic beef means that whatever they are feeding the cows has been produced without pesticides, synthetic fertilizers, or GMOs and that the animals aren’t given antibiotics, hormones or other drugs.

I should also point out that some of the farmers who operate according to organic principles choose not to go through the expensive and time-consuming organic certification process. Labeling regulations and certification programs are helpful but if you want the details on how your food is being raised, there’s really no substitute for knowing your farmer.

Is Grass-Fed Beef More Nutritious?

So far I’ve talked about farming, animal welfare, and food safety but not that much about nutrition. So let’s get to the burning question, how do corn- and grass-fed beef stack up nutritionally?

Grass-fed beef is a lot leaner than grain-fed beef and nowadays, that’s promoted as one of its chief advantages. In the interests of full disclosure, that also means that it may not be quite as tender or juicy. Leaner meat also dries out more quickly, so you have to take care not to overcook it. And the flavor of grass-fed meat is less predictable because the animals’ diets change as the local forage changes with season and location. In general, grass-fed beef is not going to be as sweet as grain-fed beef. Sometimes it can even get a little gamey tasting. Oh yeah, and because it takes more land and more time to bring the animals to slaughter, it’s going to be more expensive.

Grass fed advocates also make a big deal out of the fact that grass-fed is higher in certain nutrients such as omega-3 or beta-carotene. Although that’s absolutely true, you have to put the facts in perspective. Celery has 40 times as much sodium as cucumber, for example, but celery is still a very low-sodium food. Likewise, grass-fed meat may contain three times as much omega-3 or eight times as much beta-carotene as grain-fed beef, but it’s still not a significant source of these nutrients.

If you prefer leaner meat and happier cows, go with grass-fed. But if it’s omega-3s you’re after, eat fish. If you want more beta-carotene, eat carrots.

Is Grass Fed Beef Worth the Money?

It depends on what you’re after. Personally, I don’t think that a diet containing a moderate amount of fat or saturated fat is a problem and I get plenty of beta-carotene and omega-3 from other dietary sources. So for me, the nutritional differences between corn and grass-fed beef aren’t particularly compelling. On the other hand, I don’t believe that industrial feedlot practices are good for the environment or the cows. For that reason, more than any other, I do go out of my way to choose grass-fed organic beef. And because I only eat a few ounces of meat a month, it’s a luxury I can afford.

Source: Quick and Dirty Tips

Benefits and Risks of Eating Cod

Aaron Kandola wrote . . . . . . . . .

High in protein

Like other types of fish, cod is naturally high in protein. Specifically, 100 grams (g) of cooked cod contains around 20 g of protein.

Protein is an essential part of any diet. Proteins support the “structure, function, and regulation” of cells, tissues, and organs in the body.

Protein contains amino acids. It is essential to get some of these amino acids from food, as it is not possible for the body to make them itself. Many plant-based sources of protein do not contain these essential amino acids, but fish does.

Cod is also a healthful source of protein. There are around 0.25 g of fat and 84 calories in 100 g of cod.

Evidence suggests that obtaining protein from more healthful sources could have a range of health benefits, such as reducing the risk of diabetes and heart disease.

Less healthful sources of protein are foods such as red meat and cheese.

It is important to eat protein every day, as the body stores protein in a different way to other macronutrients such as carbohydrates.

The National Academies of Sciences, Engineering, and Medicine advise that adults aim to include at least 0.8 g of protein per kilogram of body weight in their daily diet.

Omega-3 fatty acid

The low fat content of cod mainly consists of omega-3 fatty acids. The body cannot produce omega-3 fatty acids, so people must get them from their diet.

Omega-3 fatty acids are important to cell functioning and contribute to the functioning of the cardiovascular, endocrine, and immune systems.

These fatty acids appear to have many health benefits, such as protecting against cardiovascular disease.

Omega-3 fatty acids are less common than other fatty acids, such as omega-6. Fish, including cod, is a rich source of omega-3 fatty acids.

Vitamins

Cod is a good source of several vitamins, including vitamins E, A, C. It is also an excellent source of multiple B vitamins, especially B-6 and B-12.

Vitamins perform a range of important functions in the body, and a vitamin deficiency can have negative health consequences.

For example, vitamin B-6 is important for metabolic processes and brain development. Vitamin B-12 supports nerve and blood cells. It is also important for preventing health conditions such as anemia and maintaining energy levels.

Vitamin B-12 is mostly present in animal products and fish. A person can obtain other B vitamins from both plant and animal sources. Cod contains both vitamins B-6 and B-12.

Minerals

Cod also contains multiple minerals, including phosphorus, potassium, and selenium.

Potassium supports the muscles and nervous system. Phosphorus is important for keeping bones healthy, regulating heartbeat, and maintaining kidney function. Selenium is important for thyroid function, reproduction, DNA production, and the immune system.

The body needs a range of minerals to function properly. As with vitamins, it is important to obtain minerals from the diet.

Potential risks

Consuming cod in moderate amounts is safe and generally without adverse effects.

Cod, like most types of fish, contains mercury. Excessive mercury consumption can be toxic and may cause neurological and behavioral disorders. It may be particularly problematic in children.

Fish naturally contain mercury, partly from consuming other fish. It may be worth limiting the consumption of large fish, such as swordfish, tilefish, and king mackerel. It is important to note that albacore tuna has significantly more mercury than canned light tuna.

However, cod does not contain high amounts of mercury. So, moderate consumption of cod should not cause problems in most people.

During pregnancy

In general, cod is safe for pregnant women to consume in moderate quantities.

The Food and Drug Administration (FDA) recommend that pregnant women consume 8–12 ounces (oz) of fish low in mercury. Consuming too much mercury can harm a fetus.

Cod is lower in mercury than many other fish. Eating between 8 and 12 oz of cod per week should be safe for pregnant women. Other examples of very low-mercury fish are sardines and herring.

Adding to the diet

There are many ways to add more cod to the diet, such as by consuming cod fillets.

The best method of eating a cod fillet would be to steam, grill, or bake it. It is also possible to fry the fillet, but this is a less healthful way of cooking.

Cod goes well with vegetables and in a curry. It is also possible to make cod into a pie, or to use breadcrumbs to coat the fish for added flavor.

A range of ready-made products also contain cod, such as fish cakes and fish sticks. However, these products are generally less healthful.

Summary

Cod is a highly nutritious food. It is a rich source of protein, omega-3 fatty acids, vitamins, and minerals. It is also low in calories and contains very small amounts of fat.

It is generally safe to eat in moderate amounts.

Pregnant women should consume no more than 8–12 oz of cod per week due to its mercury content.

The most healthful way to eat cod is to grill or bake the fish and combine it with a side of mixed vegetables.

Source: Medical News Today

Infographic: Aggregate Nutrient Density Index (ANDI) Scores

See large image . . . . .

Source: Dr. Fuhrman


Read also at Centers for Disease Control and Prevention:

Defining Powerhouse Fruits and Vegetables: A Nutrient Density Approach . . . . .