By now, there should be no question that many fat-rich foods are excellent additions to a healthy diet. In fact, there never was a question about the healthy side of fats. Despite all the media hype, the war on fat never really existed. The caution was on excessive consumption of specific fats—first saturated fatty acids and, later on, trans fatty acids (a.k.a. trans fats).
Now that the use of trans fats in food processing is being regulated out of existence, the focus is shifting to the beneficial aspects of fat and fat-based or fat-soluble ingredients, not just in food manufacturing (see “Slick Talk: Oil Technology in Food Product Development,” PF, May 2016.
Although a natural component in the food chain, most trans fats in the modern diet result from the process of hydrogenation, whereby unsaturated fats are actively altered to be partially hydrogenated to a point where they can mimic solid (saturated) fats in a formulation.
Some of the concerns over excessive saturated and hydrogenated fats in the diet are still relevant, at least for a small percentage of those for whom dietary fat intake has a big impact on serum fat. But continued and recent epidemiological evidence reveals effectively no difference in cardiovascular disease risk when comparing saturated to unsaturated fatty acids in healthy people.
On the other hand, such studies often get (mis)used to suggest people can load up on saturated fat, since it has “proven to be harmless.” This can be a decidedly unhealthful suggestion, since a large intake of saturated fatty acids shows a much greater potential to induce inflammation and insulin resistance than do unsaturated fatty acids. It also is inconsistent with numerous studies on the health benefits of nuts and fatty fruits (such as olives and avocados) in relation to cardiovascular disease, obesity, type 2 diabetes, and other chronic conditions common to modern industrialized nations. The benefits of unsaturated fatty acids and the foods in which they are the primary source of energy may go far beyond their calorie contribution.
Fats are not mere sources of energy. Lipid-based, healthful ingredients are indispensable to the successful functioning of brain and body. These include such ingredients as PUFAs and MUFAs; vitamins A, D, E, and K; and other lipid-activate nutraceuticals, such as co-enzyme Q10 (CoQ10). On the whole, fatty acid components are precursors to scores of compounds that control such important functions as inflammation, platelet aggregation, and smooth-muscle contraction.
Just as water is the primary solvent for the myriad of reactions upon which life depends, fat can be an equally important solvent for essential micronutrients and many other beneficial molecules. Many of these have not been sufficiently studied.
A-β-Cs of Fats
Nuts, seeds, and vegetables are rich in many beneficial fat-soluble chemicals. Plants have to protect themselves from ultraviolet light and the process of photosynthesis, both of which generate radicals that can damage membranes and other essential components.
Many of the fat-soluble components in plants function as antioxidants. Perhaps the most notable of these is beta-carotene, the pigment that gives carrots, cantaloupes, winter squash, pumpkins, and fruits like apricots and mangoes their characteristic color.
Beta-carotene is the plant precursor to fully functional vitamin A in all of its forms. Vitamin A is critical to vision; epithelial skin health; skeletal integrity, growth and development; and a functioning immune system. Beta-carotene-rich foods have shown to be protective from several diseases, including many forms of cancer, although the potential mechanisms still require much research.
A recent study published in the journal Gastroenterology drew a link between liver cancer and low levels of circulating vitamin A. In this study, persons at high risk for liver cancer, those chronically infected with hepatitis C virus, showed early depletion in blood levels of vitamin A and fat-soluble antioxidants, like beta-carotene.
One relative of beta-carotene, lycopene, is a potent antioxidant responsible for the red hue of tomatoes, watermelons, and pink grapefruit. However, it cannot be converted to vitamin A. In the study above, there also was a strong correlation between blood and liver lycopene levels—a correlation not seen with vitamin A. The suggestion was that dietary supplementation with lycopene could increase the amount of lycopene in the liver, a potential protective strategy. Lycopene has been associated with low levels of other forms of cancer, such as prostate, breast, and lung cancer.
Recent evidence suggests vitamin A also could play a beneficial role in obesity. This depends on increasing recognition of adipose tissue as more than a mere storehouse of energy. Rather, it is a dynamic endocrine organ that secretes a variety of active compounds, many of which are related to the control of inflammation. Other compounds give feedback that helps to keep energy consumption and expenditure in balance.
Leptin is a hormone that suppresses appetite and increase energy output. Adiponectin is a protein involved in the regulation of glucose levels, as well as the recall of fatty acids from adipose tissue for use in muscle. Adipose tissue also happens to contain substantial amounts of vitamin A in various forms. The suggestion is that vitamin A may help to coordinate pathways by which adipose tissue influences inflammation and energy balance. Perhaps vitamin A plays a role in controlling the complications of obesity or even the energy balance that makes obesity so difficult to resolve.
Lipids in Sight
There are hundreds of compounds related to beta-carotene that have potentially protective roles. Two of these, lutein and zeaxanthin, are found in high concentrations in the macula portion of the retina. Here, they offer protection from damaging effects of blue light and help insulate the surrounding ocular cells against oxidative stress. Blue light is just slightly longer wavelength than the damaging UV light, but it still is potentially harmful.
Many observational and interventional studies suggest lutein and zeaxanthin reduce the risk of age-related macular degeneration, among other eye diseases, but that is not the end of the story. Zeaxanthin might help prevent different forms of cancer.
Uveal melanoma is the most common cancer occurring within the eye; it is referred to as an intraocular malignant tumor. This form of cancer has a high mortality rate, due to its aggressive, metastatic nature. It generally migrates to the liver.
In cultured melanoma, zeaxanthin has been shown to reduce the invasion potential of these aggressive cells. This finding is of great interest, because previous studies demonstrated that zeaxanthin could stop the growth of uveal melanoma cells, forcing cell death. That potentially represents a dual protection from both the development and the migration of aggressive melanoma cells.
Looking toward the future, carotenoids are gaining so much attention that new and novel methods of supply are under intense scrutiny. For example, several species of microalgae accumulate high contents of carotenoids. Of particular interest is the production of lutein from microalgae, already a source of the keto-carotenoid, astaxanthin. Biotechnicians also are researching novel carotenoids synthesized by genetically engineered bacteria as a potential method of supply.
Astaxanthin is one of the most common carotenoids. It is widely distributed in algae and, subsequently, aquatic animals that eat the red-pigmented algae, such as shrimp, salmon, and crab. (Astaxanthin even is responsible for the pink color of flamingos that eat those shrimp.) Approved by the FDA as a food colorant in animal and fish feed, and for use as a dietary supplement (nutraceutical), astaxanthin exhibits greater antioxidative activity than other common carotenoids. With no known side effects, it shows great promise in cancer therapy.
Evidence suggests astaxanthin acts on several types of cancer, including oral, bladder, colon, and liver cancers, as well as leukemia. In fact, the mechanisms of action for astaxanthin are numerous, appearing to have the potential to thwart cancer at many stages of progress.
Cancer cells divide endlessly, remaining in a perpetual embryonic state, never growing up to become productive cells. They then migrate or metastasize using a variety of methods to invade healthy tissue. Astaxanthin has been shown to force cancer cells into normal, programmed cell death, as well as to prevent the migration and invasion of cells affecting a variety of different pathways.Adipose tissue is increasingly understood as not just a storehouse of energy but as an endocrine organ in its own right.
Numerous studies over the past ten years have made the case for the health benefits of nuts (see “Seeds of Change,” PF, June 2016), including reduced risk for obesity, type 2 diabetes, and cardiovascular disease. From almonds to walnuts to pistachios to peanuts (botanically a legume), the results are quite consistent. And, while approximately 80% of the calories in nuts are supplied by the oils, evidence suggests that many of the protective benefits come from the presence of fat-soluble antioxidants and other substances dissolved in the oils.
The natural sources of phytochemicals (plant chemicals) are foods that tend to be chronically underused in modern diets: vegetables, nuts, and seeds. Nuts, in particular, are rich in a variety of phytochemicals that go by such technical names as phenols, proanthocyanidins, gallate, flavonoids, phytosterols, and sphingolipids, to name a few. In many nuts, such as walnuts and almonds, the majority of the antioxidants are in the skin.
In addition to vitamin A and its related carotenoids, other fat-soluble vitamins merit increased attention. Vitamin K plays a critical role in blood clotting and other important functions, including calcium balance.
Dietary calcium is most notably linked to bone health. The bones could be thought of as the calcium bank to which calcium is added, when abundant, and from which calcium is withdrawn, when deficient.
The immediate need for calcium is muscle contraction, requiring blood levels of calcium to remain steady. Yet diets often fall short of RDA recommendations, particularly for individuals with higher needs, such as children and older adults. Dietary supplementation helps to meet these needs, but care must be taken with calcium supplementation.
Excessive supplementation can be problematic, potentially leading to arterial calcification in older adults. This is where vitamin K can help.
Vitamin K is found in different forms. Vitamin K1 is the form found in green vegetables. The other form, considered more bioactive, is K2, synthesized by bacteria, including human gut bacteria. It also is the form supplied by animal foods and fermented foods, such as bacterially fermented soy (natto). Vitamin K2 aids bone protein in binding calcium. Sufficient vitamin K2, added to a high-calcium regimen, could help prevent the accumulation of arterial calcium and promote arterial flexibility, possibly reducing the risk of cardiovascular disease.
Calcium and vitamin K work in synchronicity with vitamin D. The disease known as rickets is understood to be caused by a deficiency of this hormone-like, fat-soluble vitamin. Once the structure and pathways for vitamin D were worked out by science, foods were fortified with the so-called “sunshine vitamin” to prevent rickets, since vitamin D was not widely distributed in foods at the time.
Vitamin D deficiency began to resurge, as excessive exposure to ultraviolet light was linked to skin cancer, and fortified milk was replaced by soft drinks in the American diet. Thus, research on the vitamin increased markedly. The more science uncovered of the previously unimagined complexity of vitamin D’s role in health, studies multiplied.
Vitamin D has been linked to prevention and mitigation of a host of disease states, from cancer to cardiovascular disease, to diabetes, chronic kidney disease, hypertension, and depression. Some studies reveal a relationship between vitamin D and insulin secretion, insulin resistance, and even the function of the cells that control insulin production. It also has demonstrated promotion of immunity and anti-inflammatory responses.
It is estimated that 30-50% of people worldwide now have low levels of vitamin D. The potential relationship to chronic kidney disease is the relationship between vitamin D and the renin-angiotensin system, which controls water retention and excretion through the kidneys and directly affects blood pressure.
The Antioxidant Vitamins
Vitamin E is a potent, fat-soluble antioxidant that has been the subject of some conflicting research. The expectations related to its seeming potential to prevent disease by protecting fatty acids and membranes from oxidation have not been adequately demonstrated in intervention studies.
One issue, however, could be that there are two primary forms of vitamin E, tocopherols—one of the most widely used antioxidants in food manufacturing—and tocotrienols, which have shown highly positive results in studies of numerous forms of cancer, especially of the breast and lung. (For more on vitamin E in all its forms, see “Generation E: Healthy Characteristics of Vitamin E,” PF, January 2016.)
A recent article published in the Archives of Biochemistry and Biophysics, “The rise, the fall and the renaissance of vitamin E,” makes the case that there is still much promise for the potential of vitamin E in disease prevention, when viewed beyond its capacity as an antioxidant. The renaissance of vitamin E is based on its newly emphasized roles in cell signal transduction and gene expression. Vitamin E can be modified in the body into a compound that has been shown to decrease inflammation and enhance the immune response related to its function outside of its role as an antioxidant.
On the Q
No discussion of fat-soluble components is complete with mention of co-enzyme Q10 (CoQ10). Present in every cell in the body, CoQ10 is critical to the production of energy from food and serves as perhaps the most important fat-soluble antioxidant. Its role in energy production means that CoQ10 is most highly concentrated in hard-working muscles, especially the heart muscle.Present in every cell in the body, CoQ10 is critical to the production of energy from food.
New studies have added to its reputation as a heart-protective compound. A recently conducted trial, the so-called Q-SYMBIO trial, demonstrated a reduction in major cardiovascular events with CoQ10 supplementation in a population of patients who had heart failure, some of whom had reduced heart muscle function.
CoQ10 has taken on even more importance with recent evidence implicating cholesterol-lowering drugs referred to as statins in type 2 diabetes in women. These drugs can interfere with the synthesis of CoQ10, suggesting that CoQ10 supplementation would be prudent with these drugs, a suggestion emphasized decades ago by the late Karl Folkers,PhD, who delineated the structure of CoQ10.
Another class of lipid compounds integral to human health is that of the phospholipids, found in cell membranes and critical to everything from cell structure to cell communication (signaling) between cells. One of the major phospholipids, phosphat-idylserine, has a role to play in cell signaling, maintenance of healthy cells, clotting, and endocrine function (including as related to performance in exercise and activity). Although still preliminary, it also is believed to reduce risk of cognitive dysfunction, especially in the elderly.
Recent double-blind, placebo-controlled clinical trials revealed that a combination of phosphatidylserine and phosphatidic acid improve the stress response to “psychological and socially demanding conditions.” This was measured by reduced levels of cortisol, a hormone produced by the body in response to physical and emotional pressure and anxiety.
Naturally fat-rich foods always have been a healthy part of the human diet. Potentially beneficial fat-soluble compounds number in the hundreds, if not thousands, in addition to fat-soluble essential nutrients. Taking advantage of the health potential of these compounds will be important for the future of food processing.
Originally appeared in the July, 2016 issue of Prepared Foods as Fats for Health.
Dietary Club Med
When most people think of the Mediterranean diet, they think naturally of olive oil. The Mediterranean diet centers around the pattern of eating common to countries that border the Mediterranean Sea. Recent among the hundreds of studies supporting the health benefits of this type of diet was an intervention study that compared the effect of consuming nuts or olive oil—both high in healthful fats—with participants adhering to a Mediterranean-style diet. A control group attempted to adhere to a low-fat diet.
The study, conducted with 7,447 adults, supports the benefits of a moderate-fat diet compared to a low-fat diet. Participants in one test group consumed 30g of mixed walnuts, hazelnuts, and almonds each day. Follow-up studies, conducted both four and eight years later, revealed that both of these Mediterranean-style diets resulted in reduced rates of cardiovascular events. However, the nut-supplemented group also had a reduced risk of all-cause mortality. In fact, those who consumed nuts more than three servings per week had the lowest rates of total mortality.
The absorption of all fat-soluble compounds necessary for life depends on the consumption of at least 8% of calories from fat. In addition, there are potentially thousands of fat-soluble molecules that could play protective roles, such as reducing oxidative stress and keeping cancer cells in check.