Tag Archives: pomegranate

5 ‘superfood’ myths

While many foods may be packed with certain nutrients and molecules that play a role in health, the food industry and health nuts have taken a massive leap of logic and applied the term ‘super’ to foods which are actually fairly ordinary.

The main message here: Some foods are better for you than others but there is no such thing as a super food.

I’ve come across articles titled ’52 of the best super foods’. So pretty much all food then. It contained everything from eggs to apples. It’s all nonsense. Maintain a balanced diet and get in some good exercise. That’s it.

Here are the top 5 super foods and the real truth behind them…

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#1 : Goji Berries

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Eat me and live for 170 years guy! healthline.com
Eat me and live for 170 years guy!
healthline.com

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.These bad boys have been a major component of Chinese traditional medicine for hundreds of years.  An ancient Chinese herbalist, Li Ching-Yuen, who loved these berries, was said to have lived for over 170 years because he ate so many. Obviously that’s mental.

There is no evidence of any kind that eating the berries or drinking the juice is any better or worse than drinking juice from other fruits.

The ‘studies’ that attribute miraculous health benefits to these berries are hugely biased, poorly planned, performed, reported  and very few in number (1,2)

These berries are fairly expensive, probably because they have been labelled a super food. If you enjoy eating them then by all means carry on but don’t expect any particular health benefits for your buck.

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#2 : Kale

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'basically cabbage' lifehack.com
‘basically cabbage’
lifehack.com

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Kale, to me, seems rather exotic. It’s all the rage at the moment at organic cafes and other ‘alternative’ hangouts. Like other ‘super foods’, many magical properties have been attributed to kale – it helps you ‘make red blood cells’ and ‘mops up free radicals’ thereby reducing your risk of cancer.

While kale contains high levels of calcium and vitamins like B6, this isn’t really any different to other, similar green vegetables like cabbage. There is also no evidence supporting claims that diets high in kale can reduce cancer or really help with anything else either in humans. The limited evidence there is is all in vitro (cell based work in a lab) data which has been misinterpreted (probably on purpose) to promote kale as a super food. There is no doubt that a balanced diet with lots of vegetables is better for you than one full of processed foods (lowered risk of various cancers for one thing) but attributing the health benefits to kale alone is wrong.

Kale does contain a decent level of anti-oxidants but so do many other fruits and vegetables and other foods.

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Anti-oxidants play myriad vital roles in the body but massively increasing your intake will not improve your overall health and may even damage it (3).

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All these health food blogs keep banging on about anti-oxidants without understanding the basics tenants of biology that I keep droning on about. There is a saturation point for all nutrients and molecules past which your body just gets rid of them or maybe even starts suffering negative consequences (4). Taking more of something when you aren’t deficient in the first place very rarely produces a positive benefit. I read a good analogy online:

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”It’s like putting more petrol in your car to make it go faster”.

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Neither cars nor your body work like that.

Kale is not super. It’s no more special than your average sad piece of cabbage.

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#3 : Pomegranates

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pomegranates.org
pomegranates.org

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Pomegranates are delicious. Those little juicy nuggets of pure flavour are always welcome in my home. However things turn sour when I hear that pomegranates are not just a simple fruit – they can fight against heart disease, inflammation, high blood pressure and some cancers (the list always seems to be the same). In other words they are super. Or are they?

Now surprisingly there is some potential for further work looking at pomegranate consumption and health benefits. Although the data are currently inconclusive regarding human health – there does appear to be a positive effect in some small trials.

Pomegranate consumption has been linked to increased bone strength in mice (5).

A small study (perhaps too small) involving 45 human patients  with coronary heart disease concluded that daily pomegranate juice increased blood flow to the heart and a reduced risk of heart attack (6). The trail was small so the result could be down to chance – this is worth repeating with a larger cohort.

A study undertaken a year previously using patients with carotid artery stenosis (narrowed arteries) found that a small daily glass of pomegranate juice (50ml) over three years reduced cholesterol buildup and cholesterol-damage in the artery by almost a half. A clear reduction (7). Over ten years later and the mechanics of this are still not understood. The study also fails to demonstrate how this will positively effect stroke and heart attack rates or outcomes.

It seems, out of all of these ‘super foods’ that pomegranates have the most real evidence behind them. However, these are all small studies so the chance of a positive result occurring by chance are much higher.

One pomegranate based company has been warned by the FDA for using published data, as shown above, to make illegal claims of unproven anti-disease benefits: this is very common in the health food industry and is extremely unfair and misleading for the consumer.

In order to make specific health claims,  far larger cohort studies followed by detailed mechanistic studies would have to be performed before we label pomegranates as having any real health benefits. 

As it stands, pomegranates may have some protective effects on heart and cardiovascular health – but we need more solid data to firmly conclude this.

 

 


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#4 : Avocado

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avocado-sliced-in-half
I’m all stone baby avocado.org.au

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First off. I love avocados. I’m not here to insult them or their families – just to question there position as a ‘super food’. An avocado is a fruit, even though I think of it as a vegetable. Getting even more technical, an avocado is apparently a large berry. What?

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Avocados are packed with all sorts of deliciousness – Vitamin A, C, K and E as well as potassium and carotenoids. On top of that an avocado is basically just a big fat berry. Literally. It’s full to the brim with a wide variety of fats, with most calories from avocado being in the form of monounsaturated fat. Due to this they are a great way to gain weight if strength training or bodybuilding – just go easy on them due to the fat content!

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Now, are they super foods? Do they cure cancer or diabetes or arthritis. As you may have guessed the answer is probably no. Although the literature is very sparse regarding avocado consumption and health specifically, we can look more closely at the effects of a high intake of monounsaturated fats on our health. Eating a good amount of these fats is protective against cardio-vascular disease (8). A review of available studies looking at avocado consumption and cardiovascular disease also suggests a protective effect but be wary as the review was paid for by Hass Avocado Board (9).

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Again, any advocate of super foods will list a number of benefits and then reason them like this with little to no sources. This is an actual argument I came across:

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  1. Luetin is a carotenoid found in the human eye and plays a role in vision
  2. Avocados contain luetin
  3. Avocados improve eyesight (this is a massive leap in logic and not confirmed by any investigation)

And another to hammer the point home..

  1. Vitamin B6 plays a role in the regulation of hormones like testosterone
  2. Avocados contain B6
  3. Avocados increase fertility and sexual health (nope – for the same reasons)

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Avocados are delicious but they wont help you with sexual function, fertility, diabetes or cancer. These things may be reduced or combated by changes to your entire lifestyle – not just eating one particular giant berry.

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#5 : Broccoli

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wikipedia.org
Can’t get enough of those baby trees – Wikipedia

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When I was a young boy/girl, broccoli was the worst. It was sort of universally hated by children. I think it still is. But for adults, and the health food market, broccoli has made a solid comeback in recent years and frequents ‘super food’ lists all over the web. What does the science say about the health benefits of this baby tree vegetable?

Well unlike avocados, more research has been undertaken in this area but unfortunately most of it is very small scale, too small to be conclusive on it’s own.

First, eating more non-starchy vegetables such as broccoli (but not necessarily broccoli only) is associated with a reduced risk of some cancers, namely throat, mouth and stomach cancer. It is therefore possible that something in the broccoli is responsible but this would need to be tested directly in further trials.

There is no evidence that broccoli helps reduce blood pressure despite some claims that it does. A cohort of individuals with high blood pressure consumed daily broccoli for 4 weeks – no change was observed in their blood pressure nor was the risk of atherosclerosis reduced (10). However in a similar but positive vein, diabetic patients consuming broccoli powder daily, saw reduced levels of circulating cholesterol and triglycerides – both of which are risk factors for cardiovascular disease (11).

”Broccoli sprout powder could have favourable effects on  lipid profiles”

What about treating diabetes itself? Well, in an odd study, researchers applied the antioxidant sulforaphane (found in broccoli) to human blood vessels incubated in sugar. They were trying to mimic the conditions of chronic diabetes and elevated blood sugar levels. They found that the anti-oxidant appeared to prevent vascular damage to small blood vessels caused by high blood sugar as seen in many diabetic patients (12). As this is pure lab work using isolated tissue it remains to be seen if sulforaphane would be protective  in diabetics.

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What are your thoughts?

-ScienceGuy

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References

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1) Zi et al (1994) ”Observation of the effects of LAK/IL-2 therapy combining with Lycium barbarum polysaccharides in the treatment of 75 cancer patients’‘ Chinese Journal of Cancer Research. 16(6):428-31.

2) Amagase, H; Nance, D, H. (May 2008) ”A randomized, double-blind, placebo controlled clinical study of the general effects of standardised Lycium barbarum Juice” 14(4):403-12.

3)) Bjelakovic et al (2012) ”Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases” Cochrane Database of Systematic Reviews

4) Ristow et al (2009) ”Antioxidants prevent health promoting effects of physical exercise in humans” PNAS 106(21) 8665-86705

5) Spilmont et al (2013) ‘‘Pomegranate and its derivatives can improve bone health through decreased inflammation and oxidation stress in an animal model of postmenopausal osteoporosis” European Journal of Nutrition 53(5) 1155–1164

6) Sumner et al (2005) ”Effects of pomegranate juice consumption on myocardial perfusion in patients with coronary heart disease”  96(6):810-4.

7) Aviram et al (2008) ”Pomegranate juice consumption for 3 years by patients with carotid artery stenosis reduces common carotid intima-media thickness, blood pressure and LDL oxidation” Clinical Nutrition 23(3):423-33.

8) Sacks and Katan (2002) ”Randomised clinical trial on the effects of dietary fat and carbohydrate on plasma lipoproteins and cardiovascular disease” The American Journal of Medicine 113(9), Supplement 2. p. 13-24

9) Dreher and Davenport (2013) ”Hass avocado composition and potential health effects”  Critical Reviews in Food Science and Nutrition 53(7): 738–750.

10) Christiansen et al (2010) ”Ingestion of broccoli sprouts does not improve endothelial function in humans with hypertension” PLos One 5(8)

11) Bahadoran et al (2012) ”Broccoli sprout powder could improve serum triglyceride and oxidised LDL/LDL-cholesterol ratio in type 2 diabetic patients: a randomised double-blind placebo-controlled clinical trial’Diabetes Research and Clinical Practice  96(3):348-54

12) Mingzhan Xue et al (2008) ”Activation of NF-E2-related factor-2 reverses biochemical dysfunction of endothelial cells induced by hyperglycemia linked to vascular disease’Diabetes