Healthy Food & Healthy Living by Dr. Ayala

Can we really blame diabetes on diet choices?

Many chronic diseases are attributable, at least in part, to diet, among them are type 2 diabetes, heart disease and several forms of cancer. 

Type 2 diabetes is an enormous burden on human health and longevity worldwide, It’s has wide consequences for the people suffering from it, and on healthcare systems, as type 2 diabetes affects most organ systems including the heart, kidney, eye, brain, and liver, it increases the chances of cancers, infections, and dementia. 

Type 2 diabetes may run in families, but its rapid rise makes it clear that there’s much more than genetics at play. In the last 40 years type 2 diabetes incidence has risen 5 fold, 1 in 10 adults live with the disease and this is occurring worldwide. It’s clear that diet plays a big role, whether through weight gain and obesity or directly: by affecting sugar metabolism, inflammation, and changes in the gut. 

To what extent does your diet drive the incidence of diabetes, and which foods are most to blame?

To assess that researchers from Tufts University looked at data from 184 countries from 1990-2018. They looked at diet components, as well as age, sex, education, and where people lived. Their model relies on information from the Global Dietary Database, population demographics, global type 2 diabetes incidence estimations, and published research on how food choices impact type 2 diabetes. The findings appeared recently in Nature Medicine.

And the conclusions: about 70 percent of new cases of type 2 diabetes are attributable to a suboptimal diet and could have been avoided with a better diet. Eating too much of the wrong foods – such as refined rice and wheat, sugary drinks, processed and unprocessed meats – can explain 60 percent of the harm. Not eating enough of the protective foods – such as fruits, vegetables, nuts, seeds and whole grains – explains the 40 percent rest of the risk.

Poor diet drives type 2 diabetes in men more than in women, according to the study, in younger people more than in older ones, and in city dwellers more than in rural ones. And although men and city-dwellers with higher education tended to have a greater burden of type 2 diabetes caused by their diet, the opposite was seen in wealthier countries where living in urban areas and a higher education was predictive of a healthier diet. Interestingly, the link between a country's economic development and its diet-attributable type 2 diabetes burden has become weaker over the years – which suggests that as highly processed foods spread worldwide and expand so does type 2 diabetes.

The assessment that 70 percent of type 2 diabetes is diet related is astounding. It’s higher than previously assessed: Another study estimates 40 percent of cases are due to a suboptimal diet. This study, however, looks at 11 dietary factors instead of just six in other studies. Either way, many people could change the trajectory of their health by making healthier food choices and the biggest culprit is refined/highly processed foods – and especially refined carbs.

The diet to prevent diabetes

To lower your risk of type 2 diabetes it's important to control weight gain, which is a major risk factor for the disease. Other important lifestyle risk factors include inactivity and smoking.

Pay special attention to these diet principles to lower your risk:

Skip the sugary drinks: Excess added sugar is an established risk for diabetes, sugary drinks are the leading source of added sugar in our diet, and many studies show a clear link between soda consumption and the development of type 2 diabetes. These include randomized controlled studies that showed that sugary drinks aren’t just associated with diabetes – they cause obesity, insulin resistance and chronic inflammation, which are the harbingers of type 2 diabetes. 

Choose whole, unprocessed foods: Select whole grain over refined grains, eat nuts, beans, legumes, make sure you eat plenty of fruits and veggies (non-starchy vegetables, a potato isn’t in this category).Limit meat, especially processed meat.

Dr. Ayala

Is soda bad for your brain?

One of the biggest fears we face – especially if we’re lucky enough to live a long life – is dementia. Despite great efforts to treat Alzheimer's and other dementia forms, there is no cure for this malady. Prevention is crucial.

Important modifiable risk factors for dementia are poor nutrition, binge drinking, lack of physical activity and mental stimulation and smoking.

A new study in the American Journal of Clinical Nutrition looks at a large population of almost 180,000 people in England, with no signs of dementia at the start of the study, and follows them for an average of almost 10 years. The diet of the participants was reported, and their sugary drink consumption tallied. The genetic risk of dementia was assessed for each participant looking at common genetic variants related to the risk of Alzheimer’s disease. 

During follow-up almost 1300 of the participants developed dementia. After adjusting for socioeconomic status, lifestyle factors, such as alcohol intake, smoking, exercise and weight status, and underlying health conditions that may affect dementia risk, the researchers found that those who consumed more than 2 sugary drinks a day had greater odds of developing dementia: their risk rose by some 35 percent. Excessive intake of added sugar was also linked with dementia risk.

The added risk was seen with sugary drinks, but also with artificially sweetened ones. On the other hand, those consuming moderate amounts of fruit juices did not have a higher risk of dementia. These links were not modified by genetic predisposition.

A similar study of almost 3000 people over the age of 60 years showed almost doubling of dementia risk among those with high intake of artificially sweetened drinks, and another study of 1865 people showed greatly increased risk of dementia with an intake of on average 7 sugary drinks a week.

How could sugary drinks impair the brain? It might be that the excessive sugar and rapid rise in insulin impair the brian, and for artificially sweetened drinks the authors suggest that aspartame could disrupt energy production and increase oxidative stress.

Why are sugary drinks singled out?

The western diet contains plenty of added sugar, but while sugar’s added to many foods, most of the added sugar hides in drinks – soda, sports drinks, energy drinks, flavored milks and fruit juices – the sheer amount of sugar in sugary drinks can explain why they are linked so tightly with obesity.

But studies show that there is something distinctive about getting calories in liquid form. Solid sugars suppress hunger somewhat, while liquid sugar – in sugary drinks – doesn’t affect satiety.  Sugary drinks’ calories are just added, and the meals eaten with them will be just as large, if not larger. And several studies have suggested that sugary drinks are an independent risk factor for diabetes and hypertension irrespective of obesity. 

Liquid sugar lends itself to overconsumption, and it might very well be that sugar in liquid form poses an especially tough burden on our body’s metabolism and on our brain’s function.

Dr. Ayala 

Is honey really better than sugar?

We’re encouraged to limit sugar and sweeteners in our diet. The American Heart Association advises no more than 6 teaspoons a day for women, 9 for men, and for added sugar to provide no more than 5-10 percent of daily calories. Excess added sugar is linked with obesity, and many chronic diseases such as type 2 diabetes, metabolic syndrome and heart disease.

And since we like sweet food –  to prefer sweet foods is to be human – are there healthier ways to sweeten food? Are honey, maple syrup, agave and date syrup any better?

Sugar is sugar?

Honey is made by honeybees from the nectar of flowers, and contains, besides sugars, a whole array of organic acids, enzymes, proteins, amino acids, minerals, vitamins, and bioactive substances. It has been shown that honey has beneficial effects on sugar control, weight maintenance, inflammation, lipid profile, and as a common cold remedy.

A new systematic review published in Nutrition Reviews including 18 controlled clinical trials set to examine honey’s health effects.

It found that a median dose of 40 grams (about 2 tablespoons) daily over 8 weeks reduced blood fasting sugar, cholesterol, and triglycerides levels. Raw honey was more effective than honey that was heat treated – most of the benefits demonstrated are from studies that use raw honey.

This review is in line with animal studies: several studies in rats show that regular honey intake results in better sugar control and lipid profiles.

Honey’s wellness benefits are plausible: Honey is 80 percent sugar, mostly fructose and glucose, but there are also “rare sugars” in honey, those include monosaccharides and their derivatives (such as isomaltulose), which have effects on fats on gut microbes. Honey contains phenolic compounds and flavonoids and other important antioxidants. Raw honey contains probiotic beneficial bacteria that are known to regulate the immune system and improve lipid profiles.

The flower source of the honey also matters – clover honey, and robinia honey were especially beneficial for fasting blood sugar control and cholesterol reduction.

Swapping sugar with honey

Honey is still in the “added sugar” category, and as such, should be enjoyed in moderation. Replacing sugar with honey can help with moderation, as you’ll be skipping most processed foods – which are made with refined sugar and high fructose corn syrup. Honey’s price point and nuisance value can help limit your consumption.

A “no refined added sugar” principal that allows for natural sweeteners can make sense if it helps you keep a lid on your sweet tooth. 

The added nutrients in honey can also add a bit of wellness.

The authors of the study also suggest that honey should not be lumped with the other refined added sugars which provide nothing but energy (empty calories): “as honey, when taken in moderation, may offer a variety of benefits for glycemic control and lipid levels.”

The key is moderation. I do believe that sweets and dessert have a place in a healthy diet. But a cake doesn't become “health food” because it’s sweetened by honey – cake is still cake.

Dr. Ayala

Does the microbiome affect diabetes risk?

Type 2 diabetes is a global epidemic and one of the most common conditions impacting people's health. The incidence of this chronic disease and its many consequences is rising, as type 2 diabetes now presents at younger and younger ages. It is estimated that as many as 9.3 percent of the world population had diabetes in 2019, and that by 2030 the rates will surpass 10 percent.

The risk of developing type 2 diabetes is clearly related to obesity and to genetic predisposition. Diet is also a major contributor, but not by the simplistic way people may imagine: People with no sweet tooth at all can also be at increased risk of type 2 diabetes due to poor diets; it’s not just about eating sweets and added sugars. Diabetes is an impairment of sugar metabolism, leading to too much sugar in the bloodstream instead of our cells. Diet and exercise habits affect our body’s sugar metabolism in profound ways, and the fiber and fat that you eat, and how much you move, change how your body deals with glucose, the body’s main fuel, regardless of how much candy and soda you ingest.

Partners in sugar metabolism

But it’s not just the cell's metabolic machinery, pancreatic hormones and the liver that take part in metabolizing our sugars.

Each of us is home to a whole universe of microorganisms: trillions of bacteria, fungi and viruses. Microbial life outnumbers our own cells 9 to 1, and its genetic material outweighs our own 150 to 1. Our inhabitants, our microbiome, we’re finding out, play a role in our immune system, our endocrine system, our propensity for weight gain, our risk of several diseases, our energy levels, our mental state and our mood.  

Do the microbes living in our gut affect how our body deals with sugars and our susceptibility to type 2 diabetes?

A new study in the American Journal of Clinical Nutrition looks at the evidence connecting gut microbes to insulin resistance and glucose intolerance. The researchers identified 45 relevant studies tying specific gut bacteria to sugar metabolism. 

The researchers found that several types, 6 especially, were linked with sugar and insulin metabolism. Some of these bacteria are protective and their presence is associated with lower risk, yet the presence of other bacteria is inversely correlated with diabetes risk. These links seem to be independent of weight status and of diabetes drugs.

One of the mechanisms in which gut bacteria affect health outcomes may be their production of short chain fatty acids. Short chain fatty acids are produced by bacteria when they break down and ferment dietary fiber and resistant starch. 

And indeed, the presence of short chain fatty acids and other metabolites produced by gut bacteria seems to correlate with sugar control, suggesting that short chain fatty acids may be mediating the microbiome’s effect.

Our microbiome probably plays a role in the development of diabetes. But we also, in turn, affect our microbiome to a great extent. A study in Nature finds that just 2 percent of our gut microbiome profile is genetically determined, and the rest is affected by the environment and by lifestyle.

Helping your helpers

The gut microbial community is dynamic, and depends on many factors, including age, medications, genes, exercise,  and especially diet.

Boosting a healthy microbiome doesn’t require any probiotics, nor are any lab tests, supplements or special foods needed. To improve the gut population it’s recommended you eat whole plant foods (including many types of fruit, veggies, legumes, beans, grains etc.,) lots of fiber, embrace variety in your diet, and reduce refined and highly processed foods.

Dr. Ayala

What to eat to protect your liver

When too much fat is stored in the liver it can damage this vital organ, leading to liver inflammation, which may cause liver scarring, liver failure and liver cancer in some susceptible people. In the past most fatty liver disease was caused by heavy alcohol use. Nowadays the most common cause of excessive fat accumulation in the liver is nonalcoholic fatty liver disease – it’s unfortunately extremely common and affects about a quarter of the world population. Among people who are obese the incidence is an astounding 70 percent. The obesity epidemic is fueling the rapid rise in liver disease.

There are no FDA approved medications for nonalcoholic fatty liver disease but the good news is that this liver affliction is reversible. Diet changes and physical activity are known to improve this condition. Studies have shown that vegetables and fiber are associated with less risk of fatty liver disease, and a Western diet, high meat consumption, and soft drinks are linked with elevated risk.

A new study in the Journal of Nutrition looks at the diets of a large multiethnic group of 1682 people, whose liver composition was measured using the gold standard: MRIs quantifying fat in the organ.

The foods and nutrients linked with higher liver fat are total fat, saturated fat, cholesterol and meat.

On the other hand, fiber, vitamin C and vitamin E are significantly linked with leaner livers.

People obviously don’t eat vitamins and cholesterol as such, they eat food, and these findings suggest that the diets that are linked with liver fat storage are those high in fat, rich in animal products; those that are associated with less liver fat are more plant based (that’s where the fiber and vitamins come from). The authors conclude: “we found strong positive associations between liver fat and intakes of total fat, percentage energy from fat, and saturated fat, with meat intake a likely contributor.”

The study’s findings confirm those of previous ones. A study of 1128 Dutch people found that people with fatty liver ate more animals, soft drinks and snacks, and less fiber, and several studies show that dietary fiber is associated with lower incidence. A meta-analysis shows a dose-dependent connection between sugary drinks and non-alcoholic fatty liver disease – the more sugary drinks the higher the risk of nonalcoholic fatty liver disease. 

How do you know if you’re developing fatty liver disease?

Nonalcoholic fatty liver disease is usually silent and manifests no symptoms. People may come to medical attention if their liver enzymes – those are measured in blood tests done routinely as part of a regular checkup – are abnormal. These liver enzymes (including ALP, ALT, AST, GGT) can be an indication that the liver is inflamed or injured, and fatty liver disease is one of the common reasons for that. These tests can be followed up with imaging studies of the liver, such as an ultrasound, CT or MRI.

Lifestyle measures to protect your liver

To protect your liver avoid stressing it out: Excessive alcohol damages the liver, as can some medications. The pandemic has unfortunately led to a significant spike in alcohol consumption.

A healthy diet rich in fruits, vegetables and whole grain is as good for your liver as it is for pretty much every other part of your body. Avoid excessive added sugars, especially in drinks. Same goes for exercise. The diet-exercise holy duo also helps with avoiding weight gain, controlling cholesterol, triglycerides and abnormal sugar tolerance – which all increase the risk of extra fat deposits in your liver. 

Dr. Ayala

Healthy eating lessons from the new glycemic index data

Carbs have been demonized.  Understandably, it’s much easier to target an entire major nutrient group than to understand the intricacies of how our body interacts with the multitude of foods out there, so some lump all carbs in the to-minimize category, whether they’re an apple or a sugary drink.

But when it comes to how our body works, the quality of a food is what matters. We’ve been there before with blanket warnings about fat, only to realize that you just can’t view them all as the same thing, and you can’t develop a sensible food philosophy that aims to replace one entire major nutrient group – of which we have just three. This is nutrition reductionism to the point of silliness.

To better understand carb quality people may look at the dietary fiber content of the food and to the “added sugar” in it. Another indicator is the Glycemic Index, which measures how a food raises blood sugar. The glycemic index used to be reserved to diabetes management but it's now part of several popular weight-loss programs (South Beach, Zone) and disease prevention plans. The low glycemic index health claim is also a selling point advertised on food labels.

What is the glycemic index

The glycemic index ranks carb-containing foods on how they affect blood glucose levels when eaten in isolation. The glycemic index charts were developed by testing people’s blood sugar after ingestion of 50 grams – almost 2 ounces – of carbs from the food tested.

Carbs that break down quickly, like white bread and potatoes, have a high glycemic index. Those that release sugar into the bloodstream more gradually, like fruit, have a low glycemic index. Foods are scored on a scale of 0 to 100, and a glycemic index of ≥70 is high, 56–69 is medium, ≤55 is low.

Is the glycemic index absolute?

As you can imagine, since there are so many foods in the world, since food varies in its nutritional composition depending on cultivar and growing conditions, since foods are not eaten in isolation, because different labs are doing the testing, and due to people’s unique physiology, glycemic indexes are not and exact science.

The glycemic index also measures the response to 50 grams of carbs. Eating 50 grams of carbs from white bagels is commonplace. But although watermelon has the high glycemic index of 80 you’d have to eat almost 2 pounds of watermelon to load yourself up with 2 ounces of carbs, and therefore watermelon’s high glycemic index is irrelevant for most. To guess blood sugar responses you’d also have to take into account the glycemic load, which tallies the amount of carbs consumed.

On top of that, although the type and proportion of sugar or starch in a food affects glycemic index, so do a lot of other factors in the meal—the way the food’s been cooked, the presence of fiber, protein, fat, alcohol or acid in the meal will all affect the glucose response. Exercising and activity around a meal will affect it, too. Your own glycemic response will change from day to day.

The new glycemic index charts

Since the glycemic index’s popularity and usage are rising, and previous data is incomplete and inconsistent, a refresh of the information is overdue.

A new study in The American Journal of Clinical Nutrition looked at the glycemic index studies published to see if the older tables could be improved upon from the 2008 table. The authors reviewed published and unpublished studies and tabulated the glycemic index of about 4000 foods, more than double that of the previous table.

To generalize the 4000 results with a very broad brush:

• Fruit, legumes, pasta and dairy products have low glycemic indexes that are pretty consistent across countries.
• Cereal and cereal products, however, show a very wide variation in glycemic index, depending on the grain processing (whole grain has a lower glycemic index) and the preparation.
• Potatoes, generally a high glycemic food, varied from 84, all the way to 49, depending on the origin and cooking method. Such was the case with rice: from 73 for white rice, to 65 for brown rice.

These detailed tables will no doubt serve researchers and clinicians, as well as the general public. The glycemic index can be useful as there are studies linking low-glycemic index diets to better management and prevention of diabetes, to weight loss, and the prevention of other illnesses.

But rather than relying on a 4000 item glycemic index chart, understanding its basic themes can help us develop a healthy lifestyle pattern – no tedious counting and reference checking needed.

What the glycemic index chart teaches us is that whole plant-based foods are better, fruits and vegetables are excellent, and that lack of processing really matters. Naturally occurring carbohydrate foods also supply fiber, which is very important for health– it lowers the glycemic index, helps with satiety and promotes a healthy microbiome. Bread and rice and even potatoes won’t necessarily spike blood sugar if they’re eaten in moderate amounts and combined with other healthy foods.

For the non-diabetic, it’s much easier to follow the well-proven guidelines of limiting added sugar (sugary drinks are especially harmful), eating more plants and whole grains, and minimizing hyper-processed foods.

These dietary principles yield a low glycemic diet as an added bonus.

Dr. Ayala