This week, there are no hugely surprising news but confirmations of some old research which has been updated and generally validated. I also must confess that I have been busy with work so have not been able to allocate the usual number of hours to research into more esoteric subjects, but the following items should be comforting as there appear to be possible real-life human benefits according to some recent papers.Nitrate-rich vegetables really help
Everyone knows five portions of vegetables and fruit are helpful for maintaining good health. Lots of research have confirmed this. But one might be interested to know that a very recent paper confirmed that around 120 grams of nitrate-rich greens appear to have the most positive impact on heart health. The paper from New Edith Cowan University (ECU) is not new news as it mostly confirmed an earlier 2018 research paper funded by Isagenix International LLC. I had ignored the 2018 paper previously due to possible bias as the sponsors are a multi-level marketing company promoting and selling various dietary supplements.
The latest study, ‘Vegetable nitrate intake, blood pressure and incident cardiovascular disease: Danish Diet, Cancer, and Health Study’, released on 4 May 2021 is much more plausible, even though it mostly echoed the 2018 paper. The basic summary is that people who consumed a daily minimum quantity of nitrate-rich vegetables had on average 2.5 mmHg lower systolic blood pressure and a 12% to 26% lower risk of heart disease. These findings were based on a study size of over 50, 000 people in Denmark conducted over 23 years.
The main aim of the ECU study was identification of dietary factors which lead to lower incidences of heart disease. The primary finding was very simple: just a daily cup of raw (or half a cup of cooked) nitrate-rich vegetables was determined to have significant cardiovascular benefits. And consuming more than this daily amount (around 120 grams) did not accrue any additional benefits.
How nitrate-rich vegetables help with cardiovascular health appeared to be linked with nitric oxide levels. Nitric oxide (NO) production is significantly stimulated through enzymatic-dependent mechanisms during the dietary intake of nitrate-containing foods. NO is a primary vasodilatory factor and it is absorbed from the endothelial cells of the peripheral vasculature where it is accumulated from the digestion of nitrate-rich foods.
In summary, raised NO levels in the body arising from adequate consumption of nitrate-rich vegetables is linked to vasodilation, or the widening of the larger blood vessels such as arteries or veins. This factor contributed to a lower incidence of heart disease and reduced levels of hypertension (high blood pressure).
NO was determined to be a signalling molecule in the cardiovascular system much earlier on and this discovery had led to a Nobel prize in 1998 for Robert Furchgott, Ferid Murad and Louis Ignarro. Confirmation of the dietary associations with NO were established later.
Prior to this, the use of NO was more specific. For example, NO was introduced to cardiac patients via nitroglycerine to improve cardiovascular health, intensive care patients had NO gas included in oxygen ventilation systems to reduce dangerous high blood pressure levels, and NO had also been used to treat erectile dysfunction in men, among other interesting treatments.
Another associated paper from ECU published just over a month earlier also indicates that a nitrate-rich vegetable diet improves muscle function in the lower limbs. The study was smaller, on 3, 759 Australians, conducted over 12 years but the findings were very interesting.
The results from ‘Dietary Nitrate Intake Is Positively Associated with Muscle Function in Men and Women Independent of Physical Activity Levels’ indicated an 11% improvement in lower limb strength and a 4% faster walking speed for people who consumed higher amounts of nitrate-rich vegetables daily.
What was remarkable was the improvements in lower limb strength appeared to occur primarily from the nitrate-rich diet, regardless of the amount of any additional physical activity.
Nitrites versus nitrates
At this point, one should note the important difference between synthetic nitrites (and some synthetic nitrates) used as food preservatives (usually in meats) and natural nitrates found in green vegetables. Synthetic nitrites (and some synthetic nitrates) are commonly included in processed meats as preservatives.
However, these synthetic nitrogen-based compounds break down into nitrosamines in the human digestive system and over 90% of nitrosamines are determined to be carcinogens of varying gravity. The World Health Organisation had therefore categorised processed meats as Group 1 carcinogens in 2015.
If one finds that consumption of foods treated with nitrites is unavoidable, then include at least some other food items with high levels of ascorbic acid (vitamin C) with the meal. This helps prevent the conversion of nitrites in the stomach into nitrosamines.
Plant foods with natural nitrates
The plants containing beneficial natural nitrates make up a long list, so it is normally never a huge problem to acquire the daily suggested quantity of nitrates. Some common examples are green, leafy vegetables (like spinach, mustard greens, arugula, kale, Swiss chard and lettuce), beetroot, radishes, turnips, watercress, Chinese greens (such as bok choi, Chinese cabbage, choi sum, etc), kohlrabi, chicory leaf, celery, onion, garlic, etc.
Considering the small quantity of consumption of greens required, the health benefits appear to significantly outweigh the marginal costs and efforts involved, especially if one is susceptible to hypertension or some cardiovascular conditions.
Chocolate as a (possible) treatment for liver disease
Possibly adding to the good news is a recent April 2021 study that suggested chocolate could be a beneficial treatment for fatty liver disease and inflammation, particularly various liver conditions not associated with alcohol-related damage.
It has been claimed for many years that phytochemicals in chocolate such as polyphenols and methylxanthines have health benefits, including reduced risks of cardio-metabolic diseases including stroke, coronary heart disease and Type 2 diabetes, conditions common to obese humans. The impact of chocolate on obese mice was therefore the basis for the study.
The study outcomes were remarkably positive. However, it was regrettable the Penn State paper, ‘Dietary cocoa ameliorates non-alcoholic fatty liver disease and increases markers of antioxidant response and mitochondrial biogenesis in high fat-fed mice’ did not attempt to identify the compounds in chocolate which were claimed to promote the positive effects on the laboratory mice.
Nevertheless, compared to obese mice in the control group which were also kept on excessive diets, the chocolate-treated mice exhibited extremely interesting outcomes after eight weeks, such as 28% lower liver fat levels, 56% lower levels of oxidative stress and 75% lower levels of DNA damage. Curiously, chocolate-treated mice also gained weight at a 21% slower rate.
If the same outcomes from the mice experiments can be extrapolated to humans, the health benefits would obviously be immense. From a rational perspective however, the reality is more complicated, and there is currently no guarantee that such mice-related health improvements would apply to people, although the study is hopeful the positive results can translate to humans.
The daily dosage of chocolate required was also challenging. In the absence of precise knowledge of the actual effective compounds in chocolate, humans would require about 10 tablespoons of low-sugar cocoa powder every day to match the amount of chocolate administered to the test mice. This large daily quantity of chocolate may be a factor in the results as ingesting so much chocolate might act as an appetite inhibitor, and there is no data offered about this possible suppressant effect.
So, although the chocolate study might be good news to humans one day, until the actual active compounds in chocolate are identified, about the only thing one can presently suggest is that it may be an idea to substitute snacks without chocolate with snacks which contain chocolate. This is just a very informal suggestion, by the way, and not a recommendation.
The views expressed are entirely the writer’s own
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