Vitamin D and calcium 'reduce risk of breast cancer'

Consuming more vitamin D and calcium could help cut the risk of developing breast cancer, according to new research.

A study by 10,578 premenopausal and 20,909 postmenopausal women over the course of ten years found that higher intakes of calcium and vitamin D were moderately associated with a lower risk of breast cancer among the women who had not yet reached menopause.

The researchers at Brigham and Women's Hospital and Harvard Medical School write: "A possible explanation for the evident difference by menopause status may be related to the joint relationship among calcium, vitamin D and insulinlike growth factors."

Both calcium and vitamin D have been discovered to help stop the multiplication of breast cells which contain insulinlike growth factors. However, these growth factors decline with age, which may help explain the different results, the scientists say.

The strongest risk factor for breast cancer after gender is age; the older a woman is, the more likely she is to suffer from the illness, according to Cancer Research UK.

Lyme disease

What is Lyme disease?

Borrelia (Lyme disease) is caused by an infection resulting from a tick bite. The tick (shown above) often buries its head into the skin.

Lyme disease is an infection that derives from a tick bite. The disease has a variety of symptoms, including changes affecting the skin, heart, joints and nervous system. It is also known as borrelia or borreliosis.

What causes Lyme disease?

Lyme disease is caused by an infection from a micro-organism (Borrelia burghdor feri), itself transmitted by a bite from the wood tick, a blood-sucking parasite which normally lives on deer.

The wood tick is found in many areas, particularly in forests where deer are common. A tick will settle anywhere on a human body, but prefers warm, moist and dark places like the crotch or armpits.

When the tick has found a suitable place on the body, it sticks in its probe to draw up blood, exposing the host to the risk of infection.

What does Lyme disease feel like?

Simply seeing a tick somewhere on your body does not mean that you have contracted Lyme disease. Unfortunately, not everyone knows when they have been bitten, so consult your GP if you detect the following symptoms.

• A red spot around the location of the tick's bite. The spot will gradually grow bigger, often with a pale area in the middle. This symptom is called erythema migrans.
• Erythema migrans can also appear at other places on the body where the tick has not bitten. Some people get many red spots.
• Usually one to four weeks will pass between the bite and when erythema migrans appears.

Some patients with Lyme disease feel like they have caught influenza - the symptoms may be:

• drowsiness
• headaches
• mild fever
• joint and muscle pains
• swollen lymph glands.

What complications may occur?

Acrodermatitis chronica atrophicans

This is a condition that often develops in older women. Several years may pass from the tick bite until the development of this phenomenon. The symptoms usually involve changes in the skin around the tick bite, such as:

• swelling
• bluish or reddish discoloration of the skin.

Neuro borrelia

About 15 per cent of people with borrelia develop so-called neuro borrelia, between one and five weeks after the tick bite. The central nervous system is affected and the symptoms that result are very mixed and not specific.

• The symptoms often begin with back pain, typically between the shoulder blades and in the neck like a slipped disc. The pain worsens at night.
• Distorted feelings around the area of the bite. The nerves become numb, especially in the face. This may occur at any time up to four weeks after the pain began.
• Sometimes neuro borrelia may present itself as meningitis, with fever, headache and stiffness in the neck.
• In rare cases, the disease may become chronic, with a slowly developing destruction of the nervous system, numbing, partial hearing impairment and the development of dementia.
• Neuro borrelia demands immediate treatment, usually with an admission to hospital.

Inflammation of the joints or Lyme arthritis

This condition may present itself in days or, rarely, years after the bite, but it is very rare. The inflammation of the joints causes pain and swelling. Often, only one joint is inflamed and, rarely, more than three. The most commonly affected joint is the knee followed by the shoulder, elbow, foot, and hip. It has symptoms similar to arthritis.

When treated, the swelling will go away in about one to four weeks but it may return in later months or even years.

Effects on the heart

Lyme disease may cause:

• inflammation of the heart tissues, along with arrhythmia
• heart failure may develop in severe cases.

How does the doctor make the diagnosis?

A diagnosis of Lyme disease is more likely if the patient remembers a tick bite and presents the doctor with the erythema migrans rash.

To make a firmer diagnosis the doctor may take a blood sample to determine whether the patient has developed an antibody towards Lyme disease in their blood.

Antibodies can typically be found between two and four weeks after contracting the disease, but sometimes the antibodies do not appear for up to eight weeks. This means that people may have Lyme disease even if antibodies are not present at the very early phases, so repeat tests may be necessary in order to detect the diagnostic antibody response.

On the other hand, a positive antibody test does not necessarily mean that borrelia has recently been contracted. The antibodies may be found in the blood several years after an infection is over. Unfortunately, the antibody test is not a very efficient diagnostic tool: false-positive results are common.

If the doctor suspects neuro borrelia then hospital admission is required for tests on fluids from the spinal canal. This is to determine whether Lyme disease has entered the nervous system.

In cases of chronic neuro borrelia the treatment may include a CT scan of the nervous system.

Possible further development

With immediate and appropriate treatment the erythema migrans rash will often disappear within two weeks. Even without treatment, most cases of erythema migrans will go away without leaving permanent effects. But treatment lessens the risk of later symptoms in your nervous system and joints.

If the nervous system, joints, or heart are affected, two to three years may pass before the symptoms go away.

In rare cases a chronic disease with permanent symptoms may develop. This may happen several years after the tick bite.

What can the doctor do?

In the early stages (erythema migrans) oral antibiotic treatment may be sufficient.

If there are other symptoms, he or she will arrange hospital admission for further investigation and possible further treatment with antibiotics.

Medical treatment

Medicines used against Lyme disease include:

• oral doxycycline (eg Vibramycin) (except in children), amoxicillin (eg Amoxil)or cephalosporin antibiotics are the usual first choices.
• when antibiotics by injection are being given, then benzylpenicillin (eg Crystapen), cefotaxime (Claforan) and ceftriaxone (Rocephin) are the usual choices.
• no particular choice and method is superior to another - the decision is made by the infectious disease specialist and is dependent on the individual circumstances.

Time to talk about it – opening up on mental health

Having a mental health problem can easily lead to loneliness.

Mental health problems affect one in five of us at some point in our lives. But many people are reluctant to bring up the subject, fearing other people's reactions.

'There's still, sadly, a stigma attached to mental illness, based largely on prejudice and poor understanding. It can even be a taboo subject within the circle of family and close friends,' says Simon Lawton-Smith, head of policy at the Mental Health Foundation, which is launching its annual campaign to raise awareness about the issue.

'But any of us can develop a common mental disorder. One in four adults experience a problem in any one year – so it’s not unusual or anything to be ashamed about,' he says.

What are the most common problems?

An estimated 9 per cent of the population suffer from anxiety and depression at any one time, although many people go undiagnosed and recover without help from a doctor.

'It's been estimated that only around a quarter of people with depression receive formal care and treatment. This may be for a number of reasons – including the reluctance of people to seek help or discuss their problems,' says Lawton-Smith.

About half of people, who have anxiety and depression, will recover within 18 months.

Who is likely to be affected?

Anyone can have mental health illnesses – although poorer people, the long-term sick and unemployed people are more likely to experience problems and find them harder to overcome.

Children can, and do, suffer from mental health problems – although rates tend to increase as they reach adolescence.

Disorders affect:

• 10.4 per cent of boys aged 5 to10, rising to 12.8 per cent of boys aged 11 to15
• 5.9 per cent of girls aged 5 to10, rising to 9.65 per cent of girls aged 11 to15.

Overall, mental health disorders tend to peak in middle age.

What about dementia?

There are around 820,000 people in the UK with dementia, which is usually a disorder that affects you later in life.

But there are at least 15,000 people under the age of 65 who have the illness, many of whom are undiagnosed for a significant period of time.

'Most cases of early Alzheimer’s, and other dementias, remain undiagnosed,' explains Dr Marie Janson of the Alzheimer's Research Trust.

'Alzheimer’s Research Trust scientists are working on cutting-edge techniques to improve accurate detection, such as memory tests, brain scans and retinal examinations, which may spur on the development of new treatments and preventions for this set of diseases.

'Dementia, like other mental health problems, tends to be stigmatised, which is a barrier to people being willing to ask for help, and to receive the best care,' says Lawton-Smith.

Is a cure for dementia more likely in future?

'Dementia scientists, particularly in the UK, are making substantial progress in the race for better ways of preventing and treating dementia,' says Dr Janson.

'British scientists recently uncovered several genes that can be related toAlzheimer’s disease, while others are exploring the connection between lifestyle factors and dementia risk.

'With the right investment in research, we believe our scientists can offer hope to the hundreds of thousands, who live with this devastating condition,' she says.

What can be done about isolation and loneliness?

People with mental health issues, and their carers, may feel isolated and lonely as they deal with this issue.

Having a mental health problem can easily lead to loneliness because a person may withdraw from social situations, and they may even stop working if they’re really unwell.

A person’s carer, or partner, may also become isolated if they’re spending the bulk of their time caring.

'Everybody’s circumstances are different, but there are services and techniques available to help people overcome their isolation.

'The difficult thing is knowing where to begin. But take small steps at a pace that's comfortable and reassuring.

'Befriending and mentoring schemes run by charities and organisations can empower vulnerable people to build relationships,' says Lawton-Smith.

What can people do to help themselves and others?

'There are various things you can do, without seeking professional help – such as talking about your feelings to friends or family,' advises Lawton-Smith.

'Keep active: exercise releases chemicals in the brain that make you feel good, and regular exercise can boost your self-esteem.

'Stay in touch with friends and family, who can help share problems and offer different views to what’s going on inside your own head.

'There are strong links between how we eat and how we feel, so eat plenty of fruit and vegetables and avoid fatty foods,' he says.

Alcohol can be a temporary fix, but it will make the problem worse in the long term.

'You can seek professional help by going to your GP and being open about how you're feeling,' says Lawton-Smith.

'This isn’t a sign of weakness, and there are a range of interventions that the GP may be able to suggest to help you,' he says.

The health benefits of tomatoes

Whether you love sliced beef tomatoes, drizzled with olive oil, or tomato sauce on your linguine pasta – eating tomatoes regularly is good for your heath, as well as your palate.

Here we look at the different health benefits of tomatoes.

Wonder fruit?

Tomatoes are native to South America, but they have been grown and enjoyed in Europe for hundreds of years.

Recently, they have been linked to all kinds of health benefits.

One US study found that eating tomatoes regularly could reduce the risk of men getting prostate cancer.

The glossy red fruits (which actually come in all kinds of colours, including yellow and deep purple) are packed full of vitamins – including vitamins A, C and E.

They also contain flavonoids (natural anti-inflammatories), potassium and other mineral salts.

Tomatoes contain a high volume of water, and they're refreshing in salads on hot days. They're low in calories too, with around 14 kilocalories per 100g – approximately one and a half classic tomatoes, or five to six cherry tomatoes.

Lycopene

Lycopene may help to ward against prostate cancer.

Much of the interest in tomatoes has been due to theantioxidant lycopene – which helps to mop up damaging free radicals in the body that can harm our cells.

In fact, people living in the West get 85 per cent of this nutrient from tomatoes.

Lycopene may help to ward against:

• prostate cancer
• breast cancer
• stomach cancer
• age-related macular degeneration.

And it could boost the skins ability to protect itself against UV rays.

Some studies have suggested lycopene may play a role in reducing bad cholesterol.

Lycopene is even one of the main ingredients in new 'beauty pills'. A study carried out by the dermatology department at Charite University, in Berlin, discovered a link between lycopene based supplements and smoother, less-wrinkled skin.

Tomatoes should be eaten whole to get the full healthy effect.

'The important thing to remember is that you need the whole of the tomato to get its goodness,' says Dr Thomas Stuttaford, an expert in prostate cancer and vice-president of Prostate UK.

'Lycopene is best when combined with other bioflavonoids in tomatoes, which make the lycopene much more effective,' he says.

Sian Porter, a dietician at the British Dietetic Association, adds, 'It's important to remember that lycopene has to be taken as part of a healthy diet and lifestyle.

'It's not a magic bullet, so you can't drink, smoke and eat saturated fats and say it's OK because I'm eating tomatoes.

'It's best to eat tomatoes as part of a Mediterranean diet, with plenty of fruits and vegetables,' she says.

Which tomatoes?

Ripe, red tomatoes are likely to contain more lycopene than paler, watery ones.

This is because it's the lycopene that gives them their colour.

Gerry Hayman, spokesperson for the British Tomato Growers' Association, has investigated the lycopene content in different varieties.

'Slow-ripening, imported types of tomatoes tend to have lower levels of lycopene,' says Gerry Hayman.

'They have been bred for long-life, and this interferes with the ripening process,' he says.

'The important thing is to enjoy tomatoes – especially when you're trying to encourage children to eat them.

'Small tomatoes – such as baby plum tomatoes, cherry tomatoes and the piccolo type – tend to be sweeter. Ferrari, cocktail tomatoes and Jack Hawkins tomatoes are also good for lycopene,' he says.

Cook your tomatoes to boost the healthy effect

Lycopene is found in the cell walls of the tomato. By cooking it, more lycopene is fully released.

Cooked or heat processed tomatoes contain more lycopene, because cooking helps to release lycopene from the tomato cells.

Lycopene is fat soluble, so it helps to cook it in oil, such as olive oil.

'Eating tomato ketchup and pizza topping counts towards lycopene intake,' says Sian Porter.

'Of course that has to be weighed against additives, such as sugar and salt – and it might be better to consume tomato purée,' she says.

Since cooking reduces vitamin C, however, the British Tomato Growers’ Association suggest eating a range of fresh and cooked tomatoes.

Tomato based sauces can be eaten as a soup, added to pasta, stews, bolognese, tomato-based curries, used as a pizza topping or made into a spicy sauce to top falafels or meatballs.

Fresh tomatoes can be added to salads, sandwiches or as garnishes to a main meal.

'Taste-tastic' recipes

Basic tomato sauce

1. Start by lightly frying onion and garlic.
2. Add tomatoes (fresh or tinned), tomato purée, oregano and basil and season.
3. Cook on a gentle heat until the sauce is deep red and sticks to the back of a spoon.

This can be stored, and often tastes better the next day.

Use as a base for other dishes, such as bolognese, or add chilli for a spicy arrabiata sauce.

For a delicious bruschetta

1. Chop up ripe, flavoursome fresh tomatoes with garlic, fresh herbs and season.
2. Brush sliced ciabatta or French bread with olive oil, and toast in the oven.
3. Top with the tomatoes when done.

Knocked Me Out!

Whatever this virus is that I had really knocked the wind out of my sail! I feel old and tired.
I have spent so much of my time sleeping these past few weeks. I'm taken aback by my weakness and really bewildered by it all.
It seems not that long ago I was spending my mornings walking and bike riding with my sister Diane (I'll post about that another time), and I knew all of that was going to have to change with Jayden home from school now in the mornings, but I didn't think my mornings would take on this much of a change! Jayden and I sleep in late, and then we have a leisurely breakfast of rice and toast. Well, Jayden has the rice, a great big bowl of rice each morning (and then a bowl of chicken and rice for lunch):




My breakfast is whole grain toast with honey and cinnamon:





If the weather is not too hot and humid we eat breakfast outside:


And then Jayden spends a lot of his mornings drawing and coloring and I spend my time here at the dining table working on jigsaw puzzles:

(My daughter Ellie bought these Thomas Kinkade puzzles and they are very hard to do, I was yelling at her because they take up half the dining table, and they take so long to do. But after I got sick I was happy to have them to work on!)



(And the second one went together much quicker than the first one!)


And then it's usually nap time for us!

Listen to this bit of weirdness that happened to me while napping one day. It was the day of Jayden's graduation from Pre-K, and Ray had taken the day off, that afternoon I went out back by the pool with a pillow and laid on one of the lounge chairs to nap in the sun (it was one of my days when I could not get rid of a chill inside me). Anyway, I think that I have sleep apnea because I will wake up many nights (a few times a night) gasping for air, if you've had that happen to you, well, you know it's not a nice feeling at all!
While napping out back I dreamed that I was visiting my Mom when she was in the nursing home, and all of a sudden she said to me, "You better go", and with that, I was on my front porch and my best friend Barbara pulled up in her car, she leaned over to the passenger window and called out to me, "Eileen, breathe! Eileen, wake up, it's happening again!"
And I did wake up gasping for air.
I settled down, fell asleep, and this time dreamed I was visiting my Dad on hospice care, and he said to me, "It's time to go now", again, I was on my front porch, Barbara pulled up in her car and said, "Eileen, wake up, it's happening again."
And again, I woke up gasping for air.

And later that day while sleeping I dreamed that Raymond told me to wake up because it was going to happen again, and it did!
So I wonder is my brain triggering these episodes? Am I so fearful of it happening that I make it happen? Or is my brain trying to protect me?
Either way, very weird, right?

This sleep apnea thing (or whatever it is) isn't something new, it's been happening on and off for a few years, it just seems to have gotten worse lately.
But definitely this sleeping all the time is new! Yesterday we were at my sister-in-law Susie's house, she invited us over so we could visit with my mother-in-law Helena. Sue and Doug picked her up from Jersey on Saturday and she'll be staying with them for a few weeks (I warned Susie we might be bringing a virus into her house, she said she didn't care). It was a nice, relaxing day, just us and Jayden. Susie has a beautiful park-like yard, very big, and they have a pond, and her husband Doug had Jayden feed the turtles that were in it, and Jayden also had lots of fun swimming in their big pool.
I'm still not feeling great, and after eating my stomach was bothering me (that's what happens now, I have a stomach ache for a few hours after eating all the time now), and I laid down on their couch and proceeded to fall asleep for a few hours (if I didn't know better I would think I was bitten by a tse-tse fly)! How rude, right?! Thank goodness it wasn't the usual big crowd, so I didn't have to be too embarrassed. 

I don't know what this is that I have, but I'm going to wish it 'good riddance'!
My sister Diane thought it was food poisoning, but my oldest son came down with it last week too (he missed two days of work and he had fever and many of the same symptoms Jayden and I had), and my youngest daughter too is not feeling well now, and Ray said he feels like he's coming down with something. Whatever this crazy virus is, I wish my household (and my body) would be rid of it once and for all!

Okay, so there you have my past few weeks, not very exciting.
And now I'm off to visit with you before nap time!

Does Your Liver Look Like an Eskimo's Dinner?

Does your liver look like this?

All those white bubbles are fat droplets. 

I'm busier than a bumblebee right now, so unfortunately the high-fructose corn syrup post is going to have to wait till Tuesday.  Today I'll make a quick post about fatty liver disease. 

Someone on the Facebook version of this blog posed the question, "How common is non-alcoholic fatty liver??"

The exact prevalence in the United States is not known, but surveys suggest that far too many Americans' livers look like an Eskimo's yummy dinner plate, stuffed with as much fat as the livers of Campbell's protein-deficient, cancer-free rats. 

Fatty liver is generally asymptomatic, but can prime a person to develop inflammation, cirrhosis, and in rare cases death.  Most people who have it probably have no idea.  One author used the prevalence of diabetes and obesity to estimate that about 40 million Americans have fatty liver.  A survey of men and women in the multiracial urban population of Dallas County measured fatty liver directly and concluded that fully one third of the population had fatty liver.

Non-alcoholic fatty liver disease (NAFLD) was first described in adults in 1980 and was first described in children three years later.  The rise of the NAFLD epidemic has paralleled the rise in obesity, but you do not have to be obese to have fatty liver.  It's more closely related to insulin resistance and leptin resistance, and some people can even be extra-skinny and have fatty liver.  Over 40 percent of Americans have some form of pre-diabetes suggestive of insulin resistance.  So the true incidence may be closer to 100 million Americans rather than 40 million.

What causes fatty liver?  Dr. Robert Lustig makes an excellent case that fructose is the culprit in Sugar: The Bitter Truth.  However, even as high-fructose corn syrup began replacing sucrose and total sweetener consumption increased, another change happened: the Great Doubling of PUFA consumption during the Oiling of America.  Here's a graph from Stephan Guyenet's Whole Health Source Blog in his article "Have Seed Oils Caused a Multi-Generational Obesity Epidemic?"

I have written several blog posts on fatty liver in the past.  If you missed them, you can check them out by following these two links:

Maternal Intake of "Saturated Fat" Causes Liver Disease -- You Know, the Unsaturated Kind of Saturated Fat

Coconut Oil Not Only Protects Your Liver From Alcohol -- But From a Diet Deficient in Meat and Eggs Too!

In brief, corn oil, but not coconut oil or butter, induces fatty liver in animal experiments.  In the alcoholic model, which according to Lustig's hypothesis is the equivalent of a fructose- or sucrose-feeding model, palm oil is protective compared to fish oil; beef tallow or medium-chain fats from coconut oil are protective compared to corn oil; and cocoa butter is protective compared to corn oil.  In fact, if animals consume 40% of their diet as cocoa butter, they can consume 30% of their calories as ethanol, and they might get mighty drunk but they don't get fatty liver.

Why are PUFA's so damaging?  For a lengthy answer, check out my new article "Precious Yet Perilous -- Understanding the Essential Fatty Acids."  If you're not in the mood for a lengthy read, I describe the relationship between PUFA oxidation and atherosclerosis in myinterview with Jimmy Moore.  No reading required.

These deal mostly with heart disease, but the relationship to fatty liver is similar.  Luckily, my obligate bumblebee busy-ness is mostly occupying me with 1) fructose and 2) fatty liver right now, so look forward to a number of blog posts on fatty liver in the next week or two.  Suitable for a bumblebee, my next post will be about honey.

Potatoes and Human Health

The potato is thought to have originated in what is now Peru, on the shores of lake Titicaca. Native Peruvians such as the Quechua have been highly dependent on the potato for thousands of years. A 1964 study of the Quechua inhabitants of Nuñoa showed that they obtained 74% of their calories from potatoes (fresh and chuños), 10% from grains, 10% fromChenopodia (quinoa and cañihua), and 4% from animal foods. Total energy intake was 3,170 calories per day (1).

In 2001, a medical study of rural Quechua men reported an average body fat percentage of 16.4% (2). The mean age of the volunteers was 38. Body fat did increase slowly with age in this population, and by age 65 it was predicted to be about 20% on average. That's below the threshold of overweight, so I conclude that most men in this population are fairly lean, although there were a few overweight individuals.

In 2004, a study in rural Quechua women reported a body fat percentage of 31.2% in volunteers with a mean age of 35 (3). Body fat percentage was higher in a group of Quechua immigrants to the Peruvian capital of Lima. Among rural women, average fasting insulin was 6.8 uIU/mL, and fasting glucose was 68.4 mg/dL, which together suggest fairly good insulin sensitivity and glucose control (4). Insulin and glucose were considerably lower in the rural group than the urban group. Blood pressure was low in both groups. Overall, this suggests that Quechua women are not overweight and are in reasonably good metabolic health.

Rural Quechua are characteristically short, with the average man standing no more than 5' 2" (2). One might be tempted to speculate that this reflects stunting due to a deficient diet. However, given the fact that nearly all non-industrial populations, including contemporary hunter-gatherers, are short by modern standards, I'm not convinced the Quechua are abnormal. A more likely explanation is that industrial foods cause excessive tissue growth in modern populations, perhaps by promoting overeating and excessive insulin and IGF-1 production, which are growth factors. I first encountered this hypothesis in Dr. Staffan Lindeberg's book Food and Western Disease.

I don't consider the Quechua diet to be optimal, but it does seem to support a reasonable level of metabolic health. It shows that a lifetime high-carbohydrate, high glycemic index, high glycemic load diet doesn't lead to insulin resistance and obesity in the context of a traditional diet and lifestyle. Unfortunately, I don't have more detailed data on other aspects of their health, such as digestion.
Potato-eating Cultures: the Aymara
The Aymara are another potato-dependent people of the Andes, who span Peru, Bolivia and Chile. The first paper I'll discuss is titled "Low Prevalence of Type II Diabetes Despite a High Body Mass Index in the Aymara Natives From Chile", by Dr. Jose Luis Santos and colleagues (5). In the paper, they show that the prevalence of diabetes in this population was 1.5%, and the prevalence of pre-diabetes was 3.6%. The prevalence of both remained low even in the elderly. Here's a comparison of those numbers with figures from the modern United States (6):
That's quite a difference! The prevalence of diabetes in this population is low, but not as low as in some cultures such as the Kitavans (7, 8).

Now to discuss the "high body mass index" referenced in the title of the paper. The body mass index (BMI) is the relation between height and weight, and typically reflects fatness. The average BMI of this population was 24.9, which is very close to the cutoff between normal and overweight (25).

Investigators were surprised to find such a low prevalence of diabetes in this population, despite their apparent high prevalence of overweight. Yet if you've seen pictures of rural native South Americans, you may have noticed they're built short and thick, with wide hips and big barrel chests. Could this be confounding the relationship between BMI and body fatness? To answer that question, I found another paper that estimated body fat using skinfold measurements (9). That study found a body fat percentage of 15.4%, which is lean by any standard. Based on this paper and others, it appears that investigators shouldn't extrapolate BMI standards from modern Caucasian populations to traditional native American groups.

Back to the first paper. In this Aymara group, blood pressure was on the high side. Serum cholesterol was also a bit high for a traditionally-living population, but still lower than most modern groups (~188 mg/dL). I find it very interesting that the cholesterol level in this population that eats virtually no fat was the same as on Tokelau, where nearly half of calories come from highly saturated coconut fat (10, 11). Fasting insulin is also on the high side in the Aymara, which is also interesting given their good glucose tolerance and low prevalence of diabetes.
Potato-eating Cultures: the Irish

Potatoes were introduced to Ireland in the 17th century. They were well suited to the cool, temperate climate, and more productive than any other local crop. By the early 18th century, potatoes were the main source of calories, particularly for the poor who ate practically nothing else. In 1839, the average Irish laborer obtained 87% of his calories from potatoes (12). In 1845, the potato blight Phytophthora infestans struck, decimating potato plantations nationwide and creating the Great Famine. 
There isn't much reliable information on the health status of the Irish prior to the famine, besides reports of vitamin A deficiency symptoms (13). However, they had a very high fertility rate, and anecdotal reports described them as healthy and attractive (14):

As far as fecundity is concerned, the high nutritional value of the potato diet might have played a significant role, but little supportive evidence has been presented so far... What is known is that the Irish in general and Irish women in particular were widely described as healthy and good-looking. Adam Smith's famous remark that potatoes were "peculiarly suitable to the health of the human constitution" can be complemented with numerous observations from other contemporary observers to the same effect.

Controlled Feeding Studies

Starting nearly a century ago, a few eccentrics decided to feed volunteers a potato-only diet to see if it could be done. The first such experiment was carried out by a Dr. M. Hindhede and published in 1913 (described in 15). Hindhede's goal was to explore the lower limit of the human protein requirement and the biological quality of potato protein. He fed three healthy adult men almost nothing but potatoes and margarine for 309 days (margarine was not made from hydrogenated seed oils at the time), all while making them do progressively more demanding physical labor. They apparently remained in good physical condition. Here's a description of one of his volunteers, a Mr. Madsen, from another book (described in 16; thanks to Matt Metzgar):

In order to test whether it was possible to perform heavy work on a strict potato diet, Mr. Madsen took a place as a farm laborer... His physical condition was excellent. In his book, Dr. Hindhede shows a photograph of Mr. Madsen taken on December 21st, 1912, after he had lived for almost a year entirely on potatoes. This photograph shows a strong, solid, athletic-looking figure, all of whose muscles are well-developed, and without excess fat. ...Hindhede had him examined by five physicians, including a diagnostician, a specialist in gastric and intestinal diseases, an X-ray specialist, and a blood specialist. They all pronounced him to be in a state of perfect health.

Dr. Hindhede discovered that potato protein is high quality, providing all essential amino acids and high digestibility. Potato protein alone is sufficient to sustain an athletic man (although that doesn't make it optimal). A subsequent potato feeding study published in 1927 confirmed this finding (17). Two volunteers, a man and a woman, ate almost nothing but potatoes, lard and butter for 5.5 months. The man was an athlete but the woman was sedentary. Body weight and nitrogen balance (reflecting protein gain/loss from the body) remained constant throughout the experiment, indicating that their muscles were not atrophying at any appreciable rate, and they were probably not putting on fat. The investigators remarked:

The digestion was excellent throughout the experiment and both subjects felt very well. They did not tire of the uniform potato diet and there was no craving for change.

In one of his Paleo Diet newsletters titled "Consumption of Nightshade Plants (Part 1)", Dr. Loren Cordain referenced two feeding studies showing that potatoes increase the serum level of the inflammatory cytokine interleukin-6 (22, 23). However, one study was not designed to determine the specific role of potato in the change (two dietary factors were altered simultaneously), and the other used potato chips as the source of potato. So you'll have to pardon my skepticism that the findings are relevant to the question at hand.

Just yesterday, Mr. Chris Voigt of the Washington State Potato Commission embarked on his own n=1 potato feeding experiment as a way to promote Washington state potatoes. He'll be eating nothing but potatoes and fat for two months, and getting a full physical at the end. Check out his website for more information and updates (18). Mr. Voigt has graciously agreed to a written interview with Whole Health Source at the end of his experiment. He pointed out to me that the Russet Burbank potato, the most popular variety in the United States, is over 135 years old. Stay tuned for more interesting facts from Mr. Voigt in early December.
Observational Studies

With the recent interest in the health effects of the glycemic index, a few studies have examined the association between potatoes and health in various populations. The results are all over the place, with some showing positive associations with health, and others showing negative associations (19, 20, 21). As a whole, I find these studies difficult to interpret and not very helpful.
Anecdotes

Some people feel good when they eat potatoes. Others find that potatoes and other members of the nightshade family give them digestive problems, exacerbate their arthritis, or cause fat gain. I haven't seen any solid data to substantiate claims that nightshades aggravate arthritis or other inflammatory conditions. However, that doesn't mean there aren't individuals who are sensitive. If potatoes don't agree with you, by all means avoid them.
The Bottom Line

You made it to the end! Give yourself a pat on the back. You deserve it.

In my opinion, the scientific literature as a whole, including animal and human studies, suggests rather consistently that potatoes can be a healthy part of a varied diet for most people. Nevertheless, I wouldn't recommend eating nothing but potatoes for any length of time. If you do choose to eat potatoes, follow these simple guidelines:

• Don't eat potatoes that are green, sprouting, blemished or damaged
• Store them in a cool, dark place. They don't need to be refrigerated but it will extend their life
• Peel them before eating

Enjoy your potatoes!