There are some necessary dietary supplements

Don’t believe we are all bad, we have kept faith in a few dietary supplements even if we haven’t said so. But the list is quite short. There are certainly life situations where a supplement can be necessary as long as you can trust that what they say on the label is actually what’s in the product. And no surprises in the bottle. So here we have four supplements worth giving some thought.

Folate inadequacy

Spinach a good food source of folate (Photo: Jason Bachman).

Spinach is a good food source of folate (Photo: Jason Bachman).

For pregnant women extra folate can certainly be needed. Folate is a B-group vitamin. It is known as folate when it is found naturally in food, such as green leafy vegetables, and as folic acid, the more stable form, when it is added to food, such as bread and breakfast cereals, or used in dietary supplements. Folic acid refers to the oxidized synthetic compound, whereas folate refers to the various tetrahydrofolate derivatives naturally found in food. Folate is essential to the healthy development of babies in early pregnancy and deficiency can lead to neural tube defects such as spina bifida.

For women past childbearing age, and for men in general, excessive doses of the synthetic form of this nutrient are not necessary, and may even be harmful as it has, although not conclusively, been linked to cancer. Despite the risks associated with high levels of folic acid intake, it is well established that adequate folate intake from the consumption of folate-rich foods is essential for health.

Folate is an essential micronutrient required for the synthesis of ribo- and deoxyribonucleic acids (RNA and DNA) and thus for cell division and tissue growth, methylation reactions and amino acid metabolism. Folate aids the complete development of red blood cells, reduces levels of homocysteine in the blood, and supports nervous system function.

Excellent sources of dietary folate include vegetables such as romaine lettuce, spinach, asparagus, turnip greens, mustard greens, parsley, collard greens, broccoli, cauliflower, beets, and lentils.

We still give a green light for folate supplementation, but mainly for women of childbearing age. Folic acid supplements should contain 400 µg of folic acid to be useful. More information can be gained from a 2014 European Food Safety Authority opinion. However, there is a caveat. A study published in early 2015 showed that too much of a good thing, even for pregnant females, may predispose their daughters in particular to diabetes and obesity later in life. At least for rats. So stick to the recommended dose.

Iron deficiency

Haeme iron in meta more easily absorbed (Photo: Ryan Kazda).

Haem iron in meat more easily absorbed (Photo: Ryan Kazda).

Iron is a mineral that plays a key role in the making of red blood cells. Too little iron may lead to anaemia, a low level of red blood cells. Anaemia can cause fatigue and other symptoms.

You can certainly get enough iron from food. Iron absorption is best (15-18%) from foods that contain haem iron. Red meat, seafood and poultry are the best sources of haem iron. Iron absorption from foods that contain non-haem iron is much lower (<5%). Non-haem iron is predominantly found in plant foods such as cereals, vegetables, legumes and nuts.

In case of a deficient diet it is also possible to use iron supplements to improve iron status. Iron supplements are often used to treat anaemia caused by pregnancy, heavy menstrual periods, kidney disease and chemotherapy. Iron supplements are commonly recommended for infants and toddlers, teenage girls, and women who are pregnant or of childbearing age to help prevent anaemia.

But too much iron can lead to poisoning and cause many serious problems including stomach and intestinal distress, liver failure, dangerously low blood pressure, and death.

So again a green light for use of iron supplements but only after a diagnosis of anaemia.

Vitamin D supplementation

Vitamin D is important for several bodily functions, particularly for the maintenance of strong bones. It does that by regulating the absorption of calcium and phosphorus. Deficiency can lead to rickets in infants or osteoporotic fractures in the elderly. There are also non-skeletal actions of vitamin D with suggestions that deficiency might result in a higher incidence of cancer, cardiovascular diseases, diabetes, infections, neuropsychiatric disorders, and a higher risk of death in predominantly elderly participants living independently or in institutional care. However, there is a growing body of evidence indicating that vitamin D is unlikely to prevent non-skeletal disorders. Still there is strong support for its use from many prominent members of the research community.

Ten minutes of sunshine a day is sufficient to replenish vitamin D stores (Photo: Björn Burton).

Ten minutes of sunshine a day is sufficient to replenish vitamin D stores (Photo: Björn Burton).

The two most important forms of the vitamin are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol) that are converted in a two-step process in the liver and kidneys to calcitriol, the biologically active form. Calcitriol circulates as a hormone in the blood, regulating the concentration of calcium and phosphate in the bloodstream and promoting the healthy growth and remodeling of bone.

Sun exposure is an easy, reliable way for most people to get vitamin D. In most situations, 30 minutes of skin exposure of the arms and face to sunlight can provide all the daily vitamin D needs of the body.  Just 6 days of casual sunlight exposure without sunscreen can make up for 49 days of no sunlight exposure. Body fat acts like a kind of storage battery for vitamin D. During periods of sunlight, vitamin D is stored in fat and then released when sunlight is gone. Vitamin D can be found in small amounts in a few foods, including fatty fish such as herring, mackerel, sardines and tuna. To make vitamin D more available, it is added to dairy products, juices, and cereals.

Vitamin D deficiency has become a populist issue worldwide with increased testing for vitamin blood levels. A level of 20-50 ng/mL is considered adequate for healthy people.  If the higher level of 50 ng/mL is used as a cut-off point, a large part of the population would be deficient. At levels less than 12 ng/mL everyone agrees that supplementation would be needed.

But with so many other good things, too much can be harmful. The European Food Safety Authority has sett an upper tolerable level of vitamin D intake at 100 µg/day. More than this level could result in hypercalcaemia and lead to abnormal heart rhythms, muscle weakness, depression, abdominal pain, nausea and vomiting.

We also give a green light for vitamin D supplements but only for people with conditions such as osteoporosis or chronic kidney failure that are known to decrease vitamin D, for risk groups such as people with dark skin, and after testing that show too low blood levels of vitamin D.

A caution is in place. Supplement intake levels between 5-20 µg/day is recommended in different countries and dependent on age. Thus a supplement tablet should not contain more than a total of 20 µg. The Norwegian Food Authority (Mattilsynet) has just banned a range of vitamin D supplements on the market containing more than six times the allowable level or 120 µg per tablet so be careful what you buy. And remember that you also get some vitamin D by just stepping outside in the sun.

Omega-3 fatty acids

Omega-3 fatty acids are important for normal metabolism. The three types of omega-3 fatty acids involved in human physiology are α-linolenic acid (ALA) (found in plant oils), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) (both commonly found in marine oils). Unfortunately, humans have only a limited ability to synthesise the more important long-chain omega-3 fatty acids, EPA and DHA from ALA and this is further deteriorating with age.

Fish is the best food source of omega-3 fatty acids (Photo: Johan Munk Wolfhage).

Fish is the best food source of omega-3 fatty acids (Photo: Johan Munk Wolfhage).

There are many health benefits of omega-3 fatty acids. Research shows strong evidence that EPA and DHA can help lower triglycerides and blood pressure. And there are studies showing that omega-3 fatty acids may help with other conditions, including rheumatoid arthritis, depression, and many more. It is clear that we need omega-3 fatty acids for numerous normal body functions, such as controlling blood clotting and building cell membranes in the brain.  And dieticians say that there’s no question that eating fish provides tremendous value in reducing risk for cardiovascular disease.

There aren’t many side effects reported for omega-3 fatty acids. Some people can experience intestinal problems and gas formation, but not much else. So there should be all go for eating more fatty fish or taking fish oil supplements.

But as usual there is a catch when relying on supplements. A recent study has shown that most fish oil capsules sold in Australia and New Zealand have less omega-3 fatty acids than their labels claim. Only three of the 32 fish oil capsules tested by researchers from Newcastle University and Auckland University contained the same or higher amount of the polyunsaturated fats declared on their labels.  Two products failed to hit even a third of what was claimed. Further, the active ingredients of fish oil are fragile, and if they’re exposed to oxygen, to light, to increasing temperature above freezing, they will degrade. And true enough the researchers discovered worryingly high levels of oxidisation.

Conclusion

What we can learn is that barely a handful of food supplements are worthwhile and mainly if a deficiency has been established. So by all means go ahead. But even if the supplements are recommended you don’t know if you get what you pay for. Unless the controls of the supplements industry are improved it might be better to stay away.

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