Red meat, iron and Alzheimer’s
On 23 August 2013 news headlines were “Red meat could raise Alzheimer’s risk.”
“Iron in red meat could raise the risk of Alzheimer’s” said the Daily Mail actual newspaper. On line we had a fuller headline: “Eating too much red meat could increase the risk of Alzheimer’s: Scientists warn build-up of iron may damage the brain.”
A quick check on line revealed that the story was making global headlines: “Is iron in steak to blame for risk of Alzheimer’s? Study suggests excess red meat bad for the brain” was the story on the Canadian Global News site.
The original article
The original journal article was published online on 21 June 2013 in The Journal of Alzheimer’s Disease. The full title of the article is “Increased Iron Levels and Decreased Tissue Integrity in Hippocampus of Alzheimer’s Disease Detected in vivo with Magnetic Resonance Imaging.”
This catchy title was inexplicably overlooked until a press release was issued on the 20 August 2013, on the main Journal of Alzheimer’s Disease web site, with the more media friendly headline: “UCLA study suggests iron is at core of Alzheimer’s disease.”
I haven’t paid $27.50 to get the full article, but I can confirm that the abstract (summary) of the article makes no mention of meat, or even diet, at all (you can read it for yourself on the link to the original journal article above).
The abstract tells us that the study hypothesised that “with age, iron accumulates in the brain and may contribute to the risk of developing age-related diseases such as Alzheimer’s Disease (AD).” Previous studies of AD have (according to the abstract) shown that an area of the brain called the hippocampus is heavily damaged with AD, while the thalamus seems to be resistant to AD damage.
The study set out to assess iron levels and evidence of tissue damage in the hippocampus and thalamus in 31 people with AD compared to 68 people without the disease. The participants undertook MRI scans to quantify (ferritin) iron levels in the two areas of the brain being studied. The results were that “compared with healthy controls, AD subjects had increased (ferritin) iron in the hippocampus but not in the thalamus.”
The study concluded: “The data shows that in AD, hippocampus damage occurs in conjunction with ferritin iron accumulation. Prospective studies are needed to evaluate how increasing iron levels may influence the trajectory of tissue damage and cognitive and pathologic manifestations of AD.” i.e. we assume that the hippocampus damage and ferritin iron levels are related and further studies are needed to understand how iron levels could be related to tissue damage.
Keywords for the study were “Alzheimer’s disease, chelation, dementia, ferritin, field dependent relaxation rate increase (FDRI), iron, magnetic resonance imagining (MRI), myelin, prevention, treatment.” And that was it. No mention of red meat, diet, ingestion of iron or anything related to the headlines that were to follow.
The press release
The press release is quite a technical introduction to current thinking on Alzheimer’s – that it’s related to two proteins that can disrupt signalling between neurons. This would have the effect of impacting the body’s messaging system and would explain the cognitive impairment observed with Alzheimer’s.
The PR note explained that the study by Bartzokis and his team hypothesised that iron could be a factor and not just these two proteins. Nothing in the continuing copy looks like it would excite the world’s media (“myelin”, “oligodendrocytesm”, “oxidative damage” etc, yawn, yawn). But then we have the wakeup call in the penultimate paragraph:
Bartzokis noted: “The accumulation of iron in the brain may be influenced by modifying environmental factors, such as how much red meat and iron dietary supplements we consume and, in women, having hysterectomies before menopause.”
Red meat! Oh how the media loves a good bit of red meat bashing:
Red meat and dying and more Red meat and dying.
The mention of red meat and an overlooked study published two months earlier suddenly appears in English newspapers published in Majorca (we picked this up while on holiday) and on Fox News.
The leaps to be made
For red meat to impact Alzheimer’s, as implied, ALL of the following need to hold true:
1) Alzheimer’s sufferers need to ingest and absorb excessive dietary iron from red meat;
2) Dietary iron needs to end up in the hippocampus (and not the thalamus) area of the brain;
3) This iron needs to cause tissue damage;
4) This tissue damage needs to be responsible for Alzheimer’s.
1) Alzheimer’s sufferers need to ingest and absorb excessive dietary iron from red meat.
The study falls at the first hurdle. We don’t even know if the 31 people with Alzheimer’s Disease consumed red meat. They could all have been vegan for all we know.
The study falls at the first hurdle on a population level. The 2011 UK average iron intake was 11.8mg (p28 of the Family Food Survey) The RDI (Reference Daily Intake) for iron is 18mg. There is thus no evidence for iron excess – it is rather iron deficiency that we should worry about.
The researchers could have taken blood iron levels of the participants to see if AD sufferers and/or control people had generally excessive or deficient iron levels. This would have been a crucial piece of information – excessive iron in the blood and in one part of the brain is a very different puzzle to deficient iron in the blood and ‘excessive’ iron in one part of the brain.
The study falls at the first hurdle for another, easily assessable, nutritional reason – red meat is a source of iron, but it is by no means the best source, let alone the only source. Here is iron intake per 100g of the following foods:
– Red meat 1.5mg
– Spinach 2.7mg
– Sardines 2.9mg
– Cocoa powder 13.9mg
The USDA all foods database will tell you that the richest sources of iron are thyme, parsley and marjoram with 124mg, 98mg and 83mg of iron per 100g of product respectively. We use spices in very small quantities, however, so we should continue down the list of highest providers of iron until we find a food that we would consume in 50-100g portions. This turns out to be fortified sugary cereals, with Kellogg’s oat bran flakes having 63mg of iron per 100g of product. That’s 45 times the iron levels of our sirloin steak!
The top 20 sources of iron, according to the USDA bible, are 7 spices, 9 fortified cereals, 2 baby foods and 2 meats – whale and seal. I don’t know about you but I’ve never eaten whale or seal. I have eaten baby food, fortified cereals (thanks mum) and spices. Beef or lamb spleen is the only other meat in the top 50 – baby food makes up most of the places from 21-50. Probably because iron is a pretty vital mineral to ingest.
So why was the headline not “Bran flakes could raise the risk of Alzheimer’s”? or “Baby food could raise the risk of Alzheimer’s.” Or even oily fish or spinach or high cocoa content dark chocolate? The simple answer is that red meat bashing is a media past time and the other products are not demonised in the same way.
Finally, hurdle 1 notes that iron not only needs to be ingested, but absorbed. Iron needs vitamin C for its absorption. Hence someone with high iron intake with insufficient vitamin C intake will have deficient iron levels due to impaired absorption. Someone with moderate iron intake and high vitamin C intake is likely to optimise their blood and body iron levels. How about “Too much vitamin C can cause Alzheimer’s”?!
Back to the four steps, which need to all hold true, to justify the world headlines:
2) Dietary iron needs to end up in the hippocampus (and not the thalamus) area of the brain.
The study did not try to show that dietary intake of iron had accumulated in any part of the body. The original journal article did not even consider dietary sources of iron. Notwithstanding that the study has already fallen at the first hurdle, it also falls at the second.
3) This iron needs to cause tissue damage.
The study does not claim that iron causes tissue damage, so it openly falls at the third hurdle.
The study concludes: “hippocampus damage occurs in conjunction with ferritin iron accumulation. Prospective studies are needed to evaluate how increasing iron levels may influence the trajectory of tissue damage and cognitive and pathologic manifestations of AD.” i.e. we observe iron levels and hippocampus damage together, but studies are needed to see how these could be related.
The opening of the article offers one mechanism: “Although essential for cell function, increased tissue iron can promote oxidative damage to which the brain is especially vulnerable.”
This probably should be the starting point for further research – why are higher levels of iron found in one part of the brain and not another? Are body iron levels higher generally in people with higher levels in the hippocampus? Does iron go to the damaged tissue to repair damage or did the iron cause the damage? There is a wealth of further research to be done before going anywhere near red meat.
Talking about areas for research, the press release said that two proteins, and their impact on neurons, are currently held by “most researchers” to be the cause of Alzheimer’s. A growing number of researchers are calling Alzheimer’s “type 3 diabetes” – the response of the brain to glucose, just as type 2 diabetes is the response of the body to glucose. That would be a worthy area for research.
4) This tissue damage needs to be responsible for Alzheimer’s.
Does Alzheimer’s damage tissue in the hippocampus (and not the thalamus) or does tissue damage in the hippocampus (and not the thalamus) cause Alzheimer’s?
Bartzokis needs to get some Roland Rats or Mickey Mouses and induce the same tissue damage and see if Alzheimer’s develops.
This is the kind of assessment that the media should have done – not just leap four unproven steps and join the red meat attackers.
Dear journalists. Please – I beg you – please don’t be part of the demonisation of the food that we have been eating for the longest time in human development. Surely – if it’s something new you’re after – NOT bashing red meat would be a refreshing change!
p.s. (This was the Monday newsletter for 2 September 2013)
9 thoughts on “Red meat, iron and Alzheimer’s”
There is a difference between the iron found in meat and the iron found in all other types of food, plants. The iron in meat is bound to heme, heme-iron, and it is different, in that the body controls iron by absorption, absorbing it if it needs it. Heme iron though is not fully controlled and is absorbed at all times of iron status, meaning, it is absorbed even though the body is downregulating its absorption. It has another quality this heme iron, it binds to other iron ingested and causes it too to be absorbed. So, a cold cut sandwich, the heme iron in the cold cut will bind to the iron added to the bread and a little more iron added to the body which normally wouldn’t have been absorbed, age-related iron accumulation.
“DAILY IRON SUPPLEMENTATION DECREASES ABSORPTION EFFICIENCY OF NONHEME, BUT NOT HEME IRON”
You know there are some men who do have too much iron in their blood – rarely women because many spend most of their life being borderline anemic due to menstruation and pregnancy and their iron levels remain low even into menopause. For those men though, there is an easy solution – donate blood at regular intervals. My dad is one of those guys who tended to have high iron levels in his blood and he went to the Red Cross and donated blood 3 – 4 times a year on the advise of his doctor. Problem solved. By the way the tannins in tea inhibit the absorption of iron, so if you are are trying to build your iron stores avoid tea when eating red meat/liver or taking your supplement, if you are trying to block absorption of iron, have tea after your steak!
I agree with everything Zoe has said on this topic but I’d like to point readers to these free full text papers so they can think about some of the issues that may be involved in Alzheimer’s initiation and progression.
High ferritin levels have major effects on the morphology of erythrocytes in Alzheimer’s disease.
Neuroinflammation and Copper in Alzheimer’s Disease
It follows strategies that reduce copper/iron overload or reduce dangers from unbound iron may reduce chronic low level Neuroinflammation and so help prevent or delay the onset of AD.
In addition to following The Harcombe Diet (THD), it may be sensible (for those concerned about the potential for high ferritin levels) to become regular blood donors so iron stores are regularly reduced (this particularly applies to post-menopausal women and men of any age)
It may also be worth using Raw Milk (higher lactoferrin content in unpasteurized milk) or Lactoferrin supplements to help keep iron securely bound.
GREEN TEA and Curcumin also help prevent iron/copper behaving badly.
There are simple things we can and should be doing to reduce our risk of AD (and other conditions resulting from dysfunctional glucose metabolism) however I agree with Catherine that some of the suggestions in the book she referred to are only going to make matters worse.
We need to build up our natural immune function (vitamin d, melatonin lactoferrin) not increase our reliance on antibiotics which reduce the diversity of our natural gut microbiota.
Eating Apples will be much better than drinking apple juice.
Bad fats are those omega 6 vegetable oils not saturated fats from pastured animals Jean Carper’s suggestion to “Buy low-fat or fat-free dairy products” is going to someone with a damaged brain more harm than good.
I’m all for people reducing blood pressure naturally but I’d rather they raised potassium intake to the RDA than totally avoiding salt. I agree with her suggestion to “Give up sugary soft drinks – one study found more than two and a half soft drinks a day raised the risk of developing high blood pressure by 87 per cent” But I think reliance on pharmaceutical drugs to lower BP may not be a effective as using dietary/lifestyle strategies (See “Does treating high blood pressure do any good?” blog from Dr Malcolm Kendrick)
Updating already! The lady in question is “best-selling author” Jean Carper, at one time a “medical journalist” for an American newspaper. Thus far, I have not been able to find any information on her that says she has any actual medical qualification. The quote I included earlier comes from her best-selling book “100 Simple Things You Can Do to Prevent Alzheimer’s”. You can also call up snippets from this book, which I did. I am still horrified.
I just had to add to this subject. I was flipping through a well-known women’s weekly magazine yesterday, and stopped at an article on Alzheimer’s, which included a section on “what you can do to minimise your risk”. My mother has Alzheimer’s, so I do have a vested interest. However, five minutes later, I yelled an unrepeatable swear word, and threw the magazine down in disgust. A woman, whose name currently escapes me, and who didn’t appear to have any qualification in anything, actually stated that “saturated fat strangles the cells in the brain” so therefore (natch!!) is best avoided at all costs. Clearly, this class ignoramus has no idea of what the brain actually consists, or she would never have considered such nonsense. I will rush home this evening and check out the article again for her name! Back tomorrow with an update!
Another genius article thanks Zoe. One small thing: “past time” — should be “pastime”.
Zoe, you wrote that Alzheimer’s can be characterized as “Type 3 Diabetes” because it involves the brain’s response to glucose.
How does that fit in with the fact – which I often see stated and never denied – that the brain, unlike most other organs, requires glucose for energy?
I understand that our muscles and other organs may have evolved to run on a mixture of glucose and triglycerides, depending on whether the last meal was fruit or meat. And that eating carbs all the time can flood the blood with glucose, leading to metabolic syndrome.
But surely the brain needs glucose 24 hours a day? So how can glucose harm it?
Hi Tom – a couple of things.
1) don’t confuse the brain needing glucose with needing to eat carbs. Here’s a great article by Mark Sisson explaining how the brain can fuel on ketones and how glucose can be produced with gluconeogenesis. (The ice age only ended c. 10,000 years ago and lasted approximately 30,000 years. Human access to carbohydrates would have been minimal or non existent and yet we survived – thrived indeed.)
2) this is about too much glucose, not glucose per se. The average human needs 0.8-1.1 grams of glucose per litre of blood. The average human has c. 5 litres of blood, so that’s 4-5.5 grams of glucose in total that we should have in the blood stream at any one time. With glucose approximating to 4 cals per gram – that’s the equivalent of one teaspoon of sugar! Any more than that and the body will release insulin to turn the glucose into glycogen – the stored form of glucose – to extract ‘toxic’ glucose from the blood stream. When this process stops working properly and glucose is not effectively cleared from the blood stream, we describe the person as (type 2) diabetic. (Type 1 is when the process doesn’t work at all – usually a malfunction that occurs ‘overnight’ in children/teenagers – believed to be genetic/immune related rather than as a result of sugar consumption).
Type 2 diabetes can be the result of too much sugar/too often and the body becomes first insulin resistant and then the glucose removal process becomes increasingly impaired and type 2 diabetes is diagnosed. When glucose remains in the blood stream beyond the level that should, we observe symptoms of type 2 diabetes – tiredness, low energy, energy swings, frequent urination, thirst, weight changes etc. The smart view on Alzheimer’s is that – just as the body exhibits symptoms of excess sugar in the body, so there will be signs of excess glucose in the brain. Foggy feeling, forgetfulness, disorientation – I have seen all of these in my type 1 diabetic brother when his blood glucose levels have been too high. He can appear drunk to the point of incoherence.
Our current level and frequency of carb/glucose consumption is unprecedented. It makes complete sense to me that both human body and mind is suffering the consequences.
Hope this helps
Best wishes – Zoe
it’s the proverbial bad penny, the idea that red meat causes everything.
Assume a moment they’re right and dietary iron causes AD.
Then read junk food labels and work out how much added, supplementary iron the average person gets from Milo, breakfast cereals, yeast spreads, wheat flour and so on.
It’ll be more than they get from meat and vege.
As AD is also associated with high insulin levels and DM2, I think that that thoughtlessly added, unknown to consumers, and junk carbohydrate-associated iron is the greater risk.