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National Vegetarian Week

Vegetarian Lifestyle: Supercharge Your Diet

National Vegetarian Week: Supercharge Your Vegetarian Diet

May 16th marked the beginning of National Vegetarian Week, a campaign aimed at promoting the benefits of a meat-free lifestyle.

A balanced vegetarian diet is an extremely healthy choice. Vegetarians have lower mortality rates than the general population. A balanced vegetarian diet tends to provide higher levels of vitamin C, folate and thiamine than a carnivorous diet. It is also high in fibre, boosting digestive health and potentially lowering the risk of both type 2 diabetes and bowel cancer (1).

Alongside the many benefits of a vegetarian diet, there are also some potential pitfalls. Some essential nutrients are absorbed more poorly in vegetarians, while other nutrients may be less readily available in a meatless diet. Being aware of these factors can help vegetarians to achieve the full health benefits of a meat-free lifestyle.

Iron and Zinc

A balanced vegetarian diet actually contains a fair amount of iron, with iron intakes similar to that of meat eaters. Chickpeas, beans, lentils, whole grains and green leafy vegetables are all good vegetarian sources of iron.

The daily RNI for iron is 14.8mg for women and 8.7mg for men. However, an American study has suggested that the dietary recommendation for iron should be raised to 14mg for vegetarian men and to 33mg for vegetarian women (2). This is because the vegetarian diet is rich in phytates – compounds found in whole grains, legumes, nuts and seeds – which inhibit iron absorption.

Meat eaters on the other hand tend to get much of their iron in the form of haem iron from meat, fish and poultry, which is better absorbed.

For this reason, vegetarians should be careful to optimise their iron intake. Eating iron-rich foods with a source of vitamin C can enhance iron absorption. Some food preparation techniques, such as soaking and sprouting beans, grains and seeds, can break down phytates, making iron more bioavailable. An iron supplement may also be a sensible measure to ensure optimum intake.

Another important consideration for vegetarians is zinc intake. Again, plant-derived foods that are rich in zinc are also high in phytic acid, an inhibitor of zinc absorption. For this reason, vegetarians may benefit from a raised zinc intake to ensure that a sufficient amount is absorbed. A good vegetarian multivitamin containing iron and zinc will help to guard against any insufficiency. Including zinc-rich foods such as yoghurt, cheese, tofu, beans, lentils, nuts and seeds in your diet is important.

Vitamin D

Vitamin D deficiency is common in the UK, in both vegetarians and meat eaters. While some foods contain small amounts of vitamin D, the main source of this vitamin for vegetarians and meat eaters alike is sunlight.

Unfortunately, many of us in the UK do not get enough sun exposure throughout the year. For this reason, vitamin D supplementation is commonly recommended. Current UK recommendations are that babies, children, pregnant and breastfeeding women, elderly people and those who are confined indoors or cover up for cultural reasons should all supplement vitamin D.

An additional consideration for vegetarians is that many vitamin D supplements are sourced from animals. Some vitamin D supplements are sourced from fish oil. In addition, strict vegetarians often prefer to avoid supplements containing vitamin D3 which is made from sheep’s wool. Fortunately, alternative vitamin D supplements sourced from lichen provide well-absorbed vegan vitamin D3.

DHA: Essential Brain Food

Vegetarian sources of omega-3 include green leafy vegetables and flaxseeds. This type of omega-3 fat, ALA, is helpful for cardiovascular health.

Unfortunately, the vegetarian diet is very low in DHA, which is another type of omega-3 fat needed for optimal brain function. The main source of dietary DHA is oily fish and organ meats, though dairy and eggs also provide small amounts. A vegetarian diet with dairy and egg products only supplies around 20 mg/day of DHA (3), which is far below recommended levels.

Because of its role in brain function, DHA intake has been linked to improving both learning and memory. It is also implicated in the slowing of cognitive decline (4,5).

The simplest way for vegetarians to meet the recommended amount of DHA is to take a marine algae supplement. Omega-3 supplements made from algae are just as effective as fish oil supplements, and provide a simple and direct source of vegetarian DHA.

The Vegetarian Lifestyle

The advantages of a vegetarian diet are well studied. Vegetarians have been found to have lower blood pressure, a lower BMI and a lower risk of developing cardiovascular disease. Although some nutrients may be less available in a plant-based diet, being aware of these potential pitfalls can help to optimise your nutritional status while reaping the many benefits of a vegetarian lifestyle.

References
1. Davey G et al. (2003) EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33,883 meateaters and 31,546 non meat-eaters in the UK. Public Health Nutrition 6: 259–68.
2. Hunt J (2002) Moving toward a plant-based diet: are iron and zinc at risk? Nutrition Reviews 60 (5): 127–34.
3. 41. Sanders TA. DHA status of vegetarians. Prostaglandins Leukot Essent Fatty Acids. 2009 Aug-Sep;81(2-3):137-41.
4. 10. Su HM. Mechanisms of n-3 fatty acid-mediated development and maintenance of learning memory performance. J Nutr Biochem. 2010 May;21(5):364-73.
5. 28. Hashimoto M, Hossain S. Neuroprotective and ameliorative actions of polyunsaturated fatty acids against neuronal diseases: beneficial effect of docosahexaenoic acid on cognitive decline in Alzheimer’s disease. J Pharmacol Sci. 2011;116(2):150-62.

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Iron and Zinc Intake Linked with PMS

An iron-rich diet lowers the risk of pre-menstrual syndrome (PMS) according to a new study published in the American Journal of Epidemiology (1).

The study is one of the first to investigate whether dietary mineral intake is linked with PMS. The diets of more than 3,000 American women were analysed, with women completing three food frequency questionnaires over a 10-year period. After 10 years, 1,057 of the women were diagnosed with PMS while 1,968 of the women were free from the condition. The researchers then compared the diets of the women with PMS with the diets of the women with no symptoms. The researchers adjusted for factors known to affect PMS such as calcium intake.

The results showed that non-heme iron intake is linked to a lowered incidence of PMS. Non-heme iron is the iron found in plant foods and supplements, rather than iron from animal foods. Senior research Elizabeth Bertone-Johnson said that the women who consumed the most non-heme iron from both foods and supplements had “a 30 to 40 percent lower risk of developing PMS than women who consumed the lowest amount of non-heme iron”. The results also showed that women with the lowest iron intake were almost twice as likely to suffer with PMS compared to women with the highest intake.

“The level of iron intake at which we saw a lower risk of PMS, roughly greater than 20 mg per day, is higher than the current recommended daily allowance (RDA) for iron for pre menopausal women,” Bertone-Johnson says.

The researchers also suggested that iron may be related to PMS because it is involved in producing serotonin, a neurotransmitter that helps to regulate mood.

Juice
Vitamin C intake is linked with helping the absorption of iron

While iron supplements may of course be helpful to ensure adequate intake, it’s important to ensure that good dietary sources of iron are included each day. Good plant-based sources of iron include pulses such as lentils, beans and chickpeas, nuts and seeds, dried apricots and leafy greens such as spinach and kale. Iron-fortified cereals are another rich source. Adding citrus fruit or a glass of orange juice is also helpful as Vitamin C boosts iron absorption.

Another mineral was also highlighted by the study as significant in its influence on PMS. “We also saw some indication that high intake of zinc was associated with lower risk” Bertone-Johnson explains. The level of zinc linked to a lower risk of PMS was greater than 15mg each day which again is higher than the RDA.

Zinc is needed for the proper action of many hormones and it can also lower levels of hormones such as prolactin which are implicated in PMS.

Ensuring a good intake of zinc through the diet means eating zinc-rich meats such as venison, beef and turkey, while vegetarians should emphasise foods such as yoghurt, spinach, mushrooms and oats. Zinc from plant sources is less well-absorbed and so vegetarians may benefit from a zinc supplement to ensure adequate intake. It should be noted, however, that excessive levels of zinc can be detrimental to health and should only be taken under the supervision of a health practitioner.

More research is needed in this area to confirm the results of this study. In the meantime, however, ensuring an adequate intake of both iron and zinc seems a sensible measure for those who suffer with PMS.

References

1. Patricia O. Chocano-Bedoya, JoAnn E. Manson, Susan E. Hankinson, Susan R. Johnson, Lisa Chasan-Taber, Alayne G. Ronnenberg, Carol Bigelow, and Elizabeth R. Bertone-Johnson. Intake of Selected Minerals and Risk of Premenstrual Syndrome. American Journal of Epidemiology, 2013 DOI: 10.1093/aje/kws363.

2.Image courtesy of topfer.

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Choosing the Best Supplements: Part Two

In Part One I discussed some guidelines to help ensure that you are getting the best out of your supplements. Read on for more pointers.

Mineral Bioavailability
There isn’t much point in taking a supplement in a form that your body cannot use. Mineral bioavailability simply refers to the proportion of a mineral that is actually absorbed into the blood to be used by the body.

A ‘bioavailable’ mineral must be soluble in the intestine so that it can be absorbed. Minerals should be bound to different compounds to aid their absorption. This binding, or ‘chelation’, helps the mineral to survive the acid environment of the stomach and pass through into the small intestine for absorption.

If the mineral is bound too tightly, or not tightly enough, it can be released at the wrong time.  This is why the ‘form’ of the mineral is an important consideration.

Generally inorganic forms of minerals – carbonates, sulphates and oxides are not well absorbed. On the other hand, organic forms such as citrates, gluconates, aspartates and amino-acid chelates are more bioavailable.

Better quality minerals, i.e. those that are in a bioavailable, organic form do tend to be more expensive. However, cheaper supplements may be a false economy if they are poorly utilised by the body. Choosing a supplement becomes a case of weighing the cost of the supplement against its bioavailability. For example, in the New Optimum Nutrition Bible, Patrick Holford (1) explains that iron amino acid chelate is four times better absorbed than other forms, making it worth the additional cost.

Holford lists the most bioavailable forms of each mineral. All of the following forms are the most readily available to the body. In descending order (the very best first), he lists:

multi-nutrient
A multi-mineral supplement including Chronium, Calcium, Magnesium, Iron, Zinc, Manganese and Selenium.

Calcium – amino acid chelate, ascorbate, citrate, gluconate, carbonate

Magnesium – amino acid chelate, ascorbate, citrate, gluconate, carbonate

Iron – amino acid chelate, ascorbate, citrate, gluconate, sulphate, oxide

Zinc – picolinate, amino acid chelate, ascorbate, citrate, gluconate, sulphate

Manganese – amino acid chelate, ascorbate, citrate, gluconate

Selenium – Selenocysteine or selenomethionine, sodium selenite

Chromium – Picolinate, polynicotinate, ascorbate, gluconate

Tablets or Capsules?
Deciding between capsules or tablets is often a personal preference. Those who find tablets difficult to swallow often favour easy-to-swallow capsules. Sensitive individuals also tend to prefer capsules which are more likely to be free from fillers or binders. On the other hand, tablets can be compressed meaning that a higher dosage can be delivered in a single pill. They also allow for ‘sustained-release’ formulas. This can be useful for water-soluble vitamins such as Vitamin C, where absorption is better when given as a steady release formula rather than in a single dose.

For very sensitive individuals or for the delivery of light-sensitive nutrients such as coenzyme Q-10, capsules are the best choice. There are of course advantages to both types of supplements, which are listed below.

Capsules Tablets
Superior protection against oxygen and light Low cost
No need for fillers and binders Allows for sustained-release formulas
Odorless and tasteless Can fit more ingredients in through compression
Less gastrointestinal irritation Can be notched to divide the dose

Quality Assurance
The simplest way to be certain of the quality of a supplement is to check that it is GMP certified. Good Manufacturing Practice (GMP) is an assurance of quality of manufacture. While medical drugs are held to these strict standards, it is not currently a legal requirement for food supplements in the UK. However, most reputable supplement companies voluntarily submit their products to GMP certification. This compliance requires thorough record keeping, quality testing, and standards consistent with the manufacture of drugs.

Reference

1. Holford, P (2004) Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus.

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Zinc – an effective treatment for depression?

A recent review indicates that zinc may be an effective addition to treatment for depression (1).

Virdian Balanced Zinc Complex
A recent review indicates that zinc may be an effective addition to treatment for depression.

Zinc is a co-factor in many enzymes that are involved in brain function. In fact there have been a number of human clinical studies in recent years which have indicated that zinc may be useful in the management of mood disorders. People with depression are often low in this mineral, and improvements may be seen with supplementation. Furthermore, diets low in zinc can lead to impaired cognitive function and behavioural disturbances (2).

Depression is linked with alterations in chemical messengers, called neurotransmitters, in the brain. It is thought that zinc actually helps to regulate the transmission of the neurotransmitter glutamate, indicating that it may be helpful in addressing mood disorders (3).

The review found that “in studies that examined the effects of zinc supplementation as an adjunct to antidepressants drug treatment, zinc significantly lowered depressive symptom scores of depressed patients.”

Caution should be used when taking zinc supplements for long periods, as this can affect levels of other minerals such as copper. Many of the studies showed positive results using doses of just 25 mg per day for 6 weeks. Taking zinc as part of a high quality multivitamin and mineral supplement can help to strike a balance.

The researchers maintain that further well-designed research is required. It is also too early to say whether zinc is effective as a standalone treatment for depression. Zinc is an inexpensive supplement, and is considered safe when taken at low doses. For these reasons, zinc may represent a promising addition to the management of depression.

Written by Nadia Mason

References:

1. Lai J, Moxey A, Nowak G, Vashum K, Bailey K, McEvoy M. The efficacy of zinc supplementation in depression: Systematic review of randomised controlled trials. J Affect Disord. 2011 Jul 26. [Epub ahead of print].

2. Takeda A: Movement of zinc and its functional significance in the brain. Brain Res Brain Res Rev, 2000, 34,137–148.

3. Szewczy B, et al. Antidepressant activity of zinc and magnesium in view of the current hypotheses of antidepressant action. Pharmacological Reports. 2008, 60, 588–59

 

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Zinc may shorten common colds

As autumn and winter draw on, many of us are blighted by the common cold.  While there is still no cure for the virus, a new literature review indicates that a common supplement can reduce its duration.

Zinc may help the immune system
Studies have found that zinc and zinc lozenges may shorten the duration of the common cold by 40% (3)

The study, published in the Open Respiratory Medicine Journal, found that when given in higher doses, zinc and zinc lozenges may shorten the duration of the common cold by 40%.

There have been many studies on the effectiveness of zinc lozenges in treating colds, and results have not been consistent.  This new meta-analysis assessed 13 placebo-controlled trials in order to get a better picture of the effectiveness of the supplement.

Of the 13 trial studies, 5 used a total daily zinc dose of less than 75mg.  Each of these studies found no beneficial effect on cold duration.

Three trials used zinc acetate in daily doses of more than 75mg.  Each of these 3 studies found zinc to be beneficial, with an average of a 42% reduction in the duration of colds.

Five further trials used other forms of zinc in daily doses of more than 75mg.  Again, these trials showed benefit, with an average 20% decrease in the duration of colds.

While some studies recorded adverse effects such as unpleasant taste, no evidence was found that zinc lozenges might cause long term harm.  The study leader Dr Hemia concluded that “since a large proportion of trial participants have remained without adverse effects, zinc lozenges might be useful for them as a treatment option for the common cold.”

The therapeutic properties of zinc are thought to be due to this mineral’s ability to affect the immune response, as well as its antioxidant and anti-inflammatory properties.  In addition, zinc may actually inhibit the common cold virus (rhinovirus) (3).

For the common cold, zinc lozenges and sublingual zinc do appear to be a better option than zinc tablets or capsules.  This is because zinc lozenges dissolve in the mouth allowing the mucus membranes in the throat (and any cold virus there) to be acted on directly by the zinc.  Swallowing a capsule or tablet would not allow the zinc to work in the same way.

The trials that Dr Hemlia reviewed were each based on small numbers of participants, indicating that more research is needed in this area.  I would also add as a caveat that zinc is known to compete with other minerals in the body.  These minerals include copper and iron.  Long term intakes of high levels of any one mineral can reduce levels of another, a process called ‘competitive inhibition’.  Nevertheless, the study indicates that short-term intakes of high amounts of zinc should pose no harm, and may provide welcome relief for those suffering with winter colds.

Written by Nadia Mason, BSc MBANT NTCC CNHC

References

1. Harri Harri. Zinc Lozenges May Shorten the Duration of Colds: A Systematic Review. The Open Respiratory Medicine Journal, 2011; 5 (1): 51 DOI: 10.2174/1874306401105010051.

2. Korant BD, et al. Inhibition by zinc of rhinovirus protein cleavage: interaction of zinc with capsid polypeptides. J Virol. 1976;18(1):298-306.

3.  Image courtesy of Ambro.

 

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